Algebra Examples

$y = \frac{4 \ln (x + 9)}{x^{2}}$

Step 1

Differentiate both sides of the equation.

$\frac{d}{d x} (y) = \frac{d}{d x} (\frac{4 \ln (x + 9)}{x^{2}})$

Step 2

The derivative of $y$ with respect to $x$ is $y'$ .

$y'$

Step 3

Differentiate the right side of the equation.

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Step 3.1

Since $4$ is constant with respect to $x$ , the derivative of $\frac{4 \ln (x + 9)}{x^{2}}$ with respect to $x$ is $4 \frac{d}{d x} [\frac{\ln (x + 9)}{x^{2}}]$ .

$4 \frac{d}{d x} [\frac{\ln (x + 9)}{x^{2}}]$

Step 3.2

Differentiate using the Quotient Rule which states that $\frac{d}{d x} [\frac{f (x)}{g (x)}]$ is $\frac{g (x) \frac{d}{d x} [f (x)] - f (x) \frac{d}{d x} [g (x)]}{{g (x)}^{2}}$ where $f (x) = \ln (x + 9)$ and $g (x) = x^{2}$ .

$4 \frac{x^{2} \frac{d}{d x} [\ln (x + 9)] - \ln (x + 9) \frac{d}{d x} [x^{2}]}{{(x^{2})}^{2}}$

Step 3.3

Multiply the exponents in ${(x^{2})}^{2}$ .

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Step 3.3.1

Apply the power rule and multiply exponents, ${(a^{m})}^{n} = a^{m n}$ .

$4 \frac{x^{2} \frac{d}{d x} [\ln (x + 9)] - \ln (x + 9) \frac{d}{d x} [x^{2}]}{x^{2 \cdot 2}}$

Step 3.3.2

Multiply $2$ by $2$ .

$4 \frac{x^{2} \frac{d}{d x} [\ln (x + 9)] - \ln (x + 9) \frac{d}{d x} [x^{2}]}{x^{4}}$

Step 3.4

Differentiate using the chain rule, which states that $\frac{d}{d x} [f (g (x))]$ is $f' (g (x)) g' (x)$ where $f (x) = \ln (x)$ and $g (x) = x + 9$ .

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Step 3.4.1

To apply the Chain Rule, set $u$ as $x + 9$ .

$4 \frac{x^{2} (\frac{d}{d u} [\ln (u)] \frac{d}{d x} [x + 9]) - \ln (x + 9) \frac{d}{d x} [x^{2}]}{x^{4}}$

Step 3.4.2

The derivative of $\ln (u)$ with respect to $u$ is $\frac{1}{u}$ .

$4 \frac{x^{2} (\frac{1}{u} \frac{d}{d x} [x + 9]) - \ln (x + 9) \frac{d}{d x} [x^{2}]}{x^{4}}$

Step 3.4.3

Replace all occurrences of $u$ with $x + 9$ .

$4 \frac{x^{2} (\frac{1}{x + 9} \frac{d}{d x} [x + 9]) - \ln (x + 9) \frac{d}{d x} [x^{2}]}{x^{4}}$

Step 3.5

Differentiate.

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Step 3.5.1

Combine $\frac{1}{x + 9}$ and $x^{2}$ .

$4 \frac{\frac{x^{2}}{x + 9} \frac{d}{d x} [x + 9] - \ln (x + 9) \frac{d}{d x} [x^{2}]}{x^{4}}$

Step 3.5.2

By the Sum Rule, the derivative of $x + 9$ with respect to $x$ is $\frac{d}{d x} [x] + \frac{d}{d x} [9]$ .

$4 \frac{\frac{x^{2}}{x + 9} (\frac{d}{d x} [x] + \frac{d}{d x} [9]) - \ln (x + 9) \frac{d}{d x} [x^{2}]}{x^{4}}$

Step 3.5.3

Differentiate using the Power Rule which states that $\frac{d}{d x} [x^{n}]$ is $n x^{n - 1}$ where $n = 1$ .

$4 \frac{\frac{x^{2}}{x + 9} (1 + \frac{d}{d x} [9]) - \ln (x + 9) \frac{d}{d x} [x^{2}]}{x^{4}}$

Step 3.5.4

Since $9$ is constant with respect to $x$ , the derivative of $9$ with respect to $x$ is $0$ .

$4 \frac{\frac{x^{2}}{x + 9} (1 + 0) - \ln (x + 9) \frac{d}{d x} [x^{2}]}{x^{4}}$

Step 3.5.5

Simplify the expression.

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Step 3.5.5.1

Add $1$ and $0$ .

$4 \frac{\frac{x^{2}}{x + 9} \cdot 1 - \ln (x + 9) \frac{d}{d x} [x^{2}]}{x^{4}}$

Step 3.5.5.2

Multiply $\frac{x^{2}}{x + 9}$ by $1$ .

$4 \frac{\frac{x^{2}}{x + 9} - \ln (x + 9) \frac{d}{d x} [x^{2}]}{x^{4}}$

Step 3.6

Multiply $\frac{\frac{x^{2}}{x + 9} - \ln (x + 9) \frac{d}{d x} [x^{2}]}{x^{4}}$ by $\frac{x + 9}{x + 9}$ .

$4 (\frac{x + 9}{x + 9} \cdot \frac{\frac{x^{2}}{x + 9} - \ln (x + 9) \frac{d}{d x} [x^{2}]}{x^{4}})$

Step 3.7

Simplify terms.

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Step 3.7.1

Combine.

$4 \frac{(x + 9) (\frac{x^{2}}{x + 9} - \ln (x + 9) \frac{d}{d x} [x^{2}])}{(x + 9) x^{4}}$

Step 3.7.2

Apply the distributive property.

$4 \frac{(x + 9) \frac{x^{2}}{x + 9} + (x + 9) (- \ln (x + 9) \frac{d}{d x} [x^{2}])}{(x + 9) x^{4}}$

Step 3.7.3

Cancel the common factor of $x + 9$ .

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Step 3.7.3.1

Cancel the common factor.

$4 \frac{(x + 9) \frac{x^{2}}{x + 9} + (x + 9) (- \ln (x + 9) \frac{d}{d x} [x^{2}])}{(x + 9) x^{4}}$

Step 3.7.3.2

Rewrite the expression.

$4 \frac{x^{2} + (x + 9) (- \ln (x + 9) \frac{d}{d x} [x^{2}])}{(x + 9) x^{4}}$

Step 3.8

Differentiate using the Power Rule which states that $\frac{d}{d x} [x^{n}]$ is $n x^{n - 1}$ where $n = 2$ .

$4 \frac{x^{2} + (x + 9) (- \ln (x + 9) (2 x))}{(x + 9) x^{4}}$

Step 3.9

Combine fractions.

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Step 3.9.1

Multiply $2$ by $- 1$ .

$4 \frac{x^{2} + (x + 9) (- 2 \ln (x + 9) x)}{(x + 9) x^{4}}$

Step 3.9.2

Combine $4$ and $\frac{x^{2} + (x + 9) (- 2 \ln (x + 9) x)}{(x + 9) x^{4}}$ .

$\frac{4 (x^{2} + (x + 9) (- 2 \ln (x + 9) x))}{(x + 9) x^{4}}$

Step 3.10

Simplify.

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Step 3.10.1

Apply the distributive property.

$\frac{4 x^{2} + 4 ((x + 9) (- 2 \ln (x + 9) x))}{(x + 9) x^{4}}$

Step 3.10.2

Apply the distributive property.

$\frac{4 x^{2} + 4 ((x + 9) (- 2 \ln (x + 9) x))}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3

Simplify the numerator.

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Step 3.10.3.1

Simplify each term.

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Step 3.10.3.1.1

Simplify $- 2 \ln (x + 9)$ by moving $2$ inside the logarithm.

$\frac{4 x^{2} + 4 ((x + 9) (- \ln ({(x + 9)}^{2}) x))}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.2

Apply the distributive property.

$\frac{4 x^{2} + 4 (x (- \ln ({(x + 9)}^{2}) x) + 9 (- \ln ({(x + 9)}^{2}) x))}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.3

Rewrite using the commutative property of multiplication.

$\frac{4 x^{2} + 4 (- x (\ln ({(x + 9)}^{2}) x) + 9 (- \ln ({(x + 9)}^{2}) x))}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.4

Multiply $9 (- \ln ({(x + 9)}^{2}) x)$ .

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Step 3.10.3.1.4.1

Multiply $- 1$ by $9$ .

$\frac{4 x^{2} + 4 (- x (\ln ({(x + 9)}^{2}) x) - 9 (\ln ({(x + 9)}^{2}) x))}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.4.2

Reorder $\ln ({(x + 9)}^{2})$ and $- 9$ .

$\frac{4 x^{2} + 4 (- x (\ln ({(x + 9)}^{2}) x) - 9 \cdot \ln ({(x + 9)}^{2}) x)}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.4.3

Simplify $- 9 \cdot \ln ({(x + 9)}^{2})$ by moving $9$ inside the logarithm.

$\frac{4 x^{2} + 4 (- x (\ln ({(x + 9)}^{2}) x) - \ln ({({(x + 9)}^{2})}^{9}) x)}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.5

Simplify each term.

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Step 3.10.3.1.5.1

Multiply $x$ by $x$ by adding the exponents.

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Step 3.10.3.1.5.1.1

Move $x$ .

$\frac{4 x^{2} + 4 (- (x \cdot x) \ln ({(x + 9)}^{2}) - \ln ({({(x + 9)}^{2})}^{9}) x)}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.5.1.2

Multiply $x$ by $x$ .

$\frac{4 x^{2} + 4 (- x^{2} \ln ({(x + 9)}^{2}) - \ln ({({(x + 9)}^{2})}^{9}) x)}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.5.2

Multiply the exponents in ${({(x + 9)}^{2})}^{9}$ .

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Step 3.10.3.1.5.2.1

Apply the power rule and multiply exponents, ${(a^{m})}^{n} = a^{m n}$ .

$\frac{4 x^{2} + 4 (- x^{2} \ln ({(x + 9)}^{2}) - \ln ({(x + 9)}^{2 \cdot 9}) x)}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.5.2.2

Multiply $2$ by $9$ .

$\frac{4 x^{2} + 4 (- x^{2} \ln ({(x + 9)}^{2}) - \ln ({(x + 9)}^{18}) x)}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.6

Apply the distributive property.

$\frac{4 x^{2} + 4 (- x^{2} \ln ({(x + 9)}^{2})) + 4 (- \ln ({(x + 9)}^{18}) x)}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.7

Multiply $4 (- x^{2} \ln ({(x + 9)}^{2}))$ .

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Step 3.10.3.1.7.1

Multiply $- 1$ by $4$ .

$\frac{4 x^{2} - 4 (x^{2} \ln ({(x + 9)}^{2})) + 4 (- \ln ({(x + 9)}^{18}) x)}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.7.2

Simplify $- 4 \ln ({(x + 9)}^{2})$ by moving $4$ inside the logarithm.

$\frac{4 x^{2} + x^{2} (- \ln ({({(x + 9)}^{2})}^{4})) + 4 (- \ln ({(x + 9)}^{18}) x)}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.8

Multiply $4 (- \ln ({(x + 9)}^{18}) x)$ .

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Step 3.10.3.1.8.1

Multiply $- 1$ by $4$ .

$\frac{4 x^{2} + x^{2} (- \ln ({({(x + 9)}^{2})}^{4})) - 4 (\ln ({(x + 9)}^{18}) x)}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.8.2

Reorder $\ln ({(x + 9)}^{18})$ and $- 4$ .

$\frac{4 x^{2} + x^{2} (- \ln ({({(x + 9)}^{2})}^{4})) - 4 \cdot \ln ({(x + 9)}^{18}) x}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.8.3

Simplify $- 4 \cdot \ln ({(x + 9)}^{18})$ by moving $4$ inside the logarithm.

$\frac{4 x^{2} + x^{2} (- \ln ({({(x + 9)}^{2})}^{4})) - \ln ({({(x + 9)}^{18})}^{4}) x}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.9

Simplify each term.

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Step 3.10.3.1.9.1

Rewrite using the commutative property of multiplication.

$\frac{4 x^{2} - x^{2} \ln ({({(x + 9)}^{2})}^{4}) - \ln ({({(x + 9)}^{18})}^{4}) x}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.9.2

Multiply the exponents in ${({(x + 9)}^{2})}^{4}$ .

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Step 3.10.3.1.9.2.1

Apply the power rule and multiply exponents, ${(a^{m})}^{n} = a^{m n}$ .

$\frac{4 x^{2} - x^{2} \ln ({(x + 9)}^{2 \cdot 4}) - \ln ({({(x + 9)}^{18})}^{4}) x}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.9.2.2

Multiply $2$ by $4$ .

$\frac{4 x^{2} - x^{2} \ln ({(x + 9)}^{8}) - \ln ({({(x + 9)}^{18})}^{4}) x}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.9.3

Multiply the exponents in ${({(x + 9)}^{18})}^{4}$ .

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Step 3.10.3.1.9.3.1

Apply the power rule and multiply exponents, ${(a^{m})}^{n} = a^{m n}$ .

$\frac{4 x^{2} - x^{2} \ln ({(x + 9)}^{8}) - \ln ({(x + 9)}^{18 \cdot 4}) x}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.1.9.3.2

Multiply $18$ by $4$ .

$\frac{4 x^{2} - x^{2} \ln ({(x + 9)}^{8}) - \ln ({(x + 9)}^{72}) x}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.3.2

Reorder factors in $4 x^{2} - x^{2} \ln ({(x + 9)}^{8}) - \ln ({(x + 9)}^{72}) x$ .

$\frac{4 x^{2} - x^{2} \ln ({(x + 9)}^{8}) - x \ln ({(x + 9)}^{72})}{x \cdot x^{4} + 9 x^{4}}$

Step 3.10.4

Multiply $x$ by $x^{4}$ by adding the exponents.

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Step 3.10.4.1

Multiply $x$ by $x^{4}$ .

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Step 3.10.4.1.1

Raise $x$ to the power of $1$ .

$\frac{4 x^{2} - x^{2} \ln ({(x + 9)}^{8}) - x \ln ({(x + 9)}^{72})}{x^{1} x^{4} + 9 x^{4}}$

Step 3.10.4.1.2

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$\frac{4 x^{2} - x^{2} \ln ({(x + 9)}^{8}) - x \ln ({(x + 9)}^{72})}{x^{1 + 4} + 9 x^{4}}$

Step 3.10.4.2

Add $1$ and $4$ .

$\frac{4 x^{2} - x^{2} \ln ({(x + 9)}^{8}) - x \ln ({(x + 9)}^{72})}{x^{5} + 9 x^{4}}$

Step 3.10.5

Factor $x$ out of $4 x^{2} - x^{2} \ln ({(x + 9)}^{8}) - x \ln ({(x + 9)}^{72})$ .

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Step 3.10.5.1

Factor $x$ out of $4 x^{2}$ .

$\frac{x (4 x) - x^{2} \ln ({(x + 9)}^{8}) - x \ln ({(x + 9)}^{72})}{x^{5} + 9 x^{4}}$

Step 3.10.5.2

Factor $x$ out of $- x^{2} \ln ({(x + 9)}^{8})$ .

$\frac{x (4 x) + x (- x \ln ({(x + 9)}^{8})) - x \ln ({(x + 9)}^{72})}{x^{5} + 9 x^{4}}$

Step 3.10.5.3

Factor $x$ out of $- x \ln ({(x + 9)}^{72})$ .

$\frac{x (4 x) + x (- x \ln ({(x + 9)}^{8})) + x (- \ln ({(x + 9)}^{72}))}{x^{5} + 9 x^{4}}$

Step 3.10.5.4

Factor $x$ out of $x (4 x) + x (- x \ln ({(x + 9)}^{8}))$ .

$\frac{x (4 x - x \ln ({(x + 9)}^{8})) + x (- \ln ({(x + 9)}^{72}))}{x^{5} + 9 x^{4}}$

Step 3.10.5.5

Factor $x$ out of $x (4 x - x \ln ({(x + 9)}^{8})) + x (- \ln ({(x + 9)}^{72}))$ .

$\frac{x (4 x - x \ln ({(x + 9)}^{8}) - \ln ({(x + 9)}^{72}))}{x^{5} + 9 x^{4}}$

Step 3.10.6

Factor $x^{4}$ out of $x^{5} + 9 x^{4}$ .

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Step 3.10.6.1

Factor $x^{4}$ out of $x^{5}$ .

$\frac{x (4 x - x \ln ({(x + 9)}^{8}) - \ln ({(x + 9)}^{72}))}{x^{4} x + 9 x^{4}}$

Step 3.10.6.2

Factor $x^{4}$ out of $9 x^{4}$ .

$\frac{x (4 x - x \ln ({(x + 9)}^{8}) - \ln ({(x + 9)}^{72}))}{x^{4} x + x^{4} \cdot 9}$

Step 3.10.6.3

Factor $x^{4}$ out of $x^{4} x + x^{4} \cdot 9$ .

$\frac{x (4 x - x \ln ({(x + 9)}^{8}) - \ln ({(x + 9)}^{72}))}{x^{4} (x + 9)}$

Step 3.10.7

Expand $\ln ({(x + 9)}^{8})$ by moving $8$ outside the logarithm.

$\frac{x (4 x - x (8 \ln (x + 9)) - \ln ({(x + 9)}^{72}))}{x^{4} (x + 9)}$

Step 3.10.8

Expand $\ln ({(x + 9)}^{72})$ by moving $72$ outside the logarithm.

$\frac{x (4 x - x (8 \ln (x + 9)) - (72 \ln (x + 9)))}{x^{4} (x + 9)}$

Step 3.10.9

Cancel the common factors.

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Step 3.10.9.1

Factor $x$ out of $x^{4} (x + 9)$ .

$\frac{x (4 x - x (8 \ln (x + 9)) - (72 \ln (x + 9)))}{x (x^{3} (x + 9))}$

Step 3.10.9.2

Cancel the common factor.

$\frac{x (4 x - x (8 \ln (x + 9)) - (72 \ln (x + 9)))}{x (x^{3} (x + 9))}$

Step 3.10.9.3

Rewrite the expression.

$\frac{4 x - x (8 \ln (x + 9)) - (72 \ln (x + 9))}{x^{3} (x + 9)}$

Step 3.10.10

Simplify the numerator.

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Step 3.10.10.1

Multiply $8$ by $- 1$ .

$\frac{4 x - 8 x \ln (x + 9) - 1 \cdot 72 \ln (x + 9)}{x^{3} (x + 9)}$

Step 3.10.10.2

Multiply $- 1$ by $72$ .

$\frac{4 x - 8 x \ln (x + 9) - 72 \ln (x + 9)}{x^{3} (x + 9)}$

Step 3.10.10.3

Factor $4$ out of $4 x - 8 x \ln (x + 9) - 72 \ln (x + 9)$ .

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Step 3.10.10.3.1

Factor $4$ out of $4 x$ .

$\frac{4 (x) - 8 x \ln (x + 9) - 72 \ln (x + 9)}{x^{3} (x + 9)}$

Step 3.10.10.3.2

Factor $4$ out of $- 8 x \ln (x + 9)$ .

$\frac{4 (x) + 4 (- 2 x \ln (x + 9)) - 72 \ln (x + 9)}{x^{3} (x + 9)}$

Step 3.10.10.3.3

Factor $4$ out of $- 72 \ln (x + 9)$ .

$\frac{4 (x) + 4 (- 2 x \ln (x + 9)) + 4 (- 18 \ln (x + 9))}{x^{3} (x + 9)}$

Step 3.10.10.3.4

Factor $4$ out of $4 (x) + 4 (- 2 x \ln (x + 9))$ .

$\frac{4 (x - 2 x \ln (x + 9)) + 4 (- 18 \ln (x + 9))}{x^{3} (x + 9)}$

Step 3.10.10.3.5

Factor $4$ out of $4 (x - 2 x \ln (x + 9)) + 4 (- 18 \ln (x + 9))$ .

$\frac{4 (x - 2 x \ln (x + 9) - 18 \ln (x + 9))}{x^{3} (x + 9)}$

Step 4

Reform the equation by setting the left side equal to the right side.

$y' = \frac{4 (x - 2 x \ln (x + 9) - 18 \ln (x + 9))}{x^{3} (x + 9)}$

Step 5

Replace $y'$ with $\frac{d y}{d x}$ .

$\frac{d y}{d x} = \frac{4 (x - 2 x \ln (x + 9) - 18 \ln (x + 9))}{x^{3} (x + 9)}$