Algebra Examples

What is the value of $y$ when $x = - 2$ in the equation $y = 3 x^{3} - 4$ ?

Step 1

Replace all occurrences of $x$ with $- 2$ in each equation.

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Step 1.1

Replace all occurrences of $x$ in $y = 3 x^{3} - 4$ with $- 2$ .

$y = 3 {(- 2)}^{3} - 4$

$x = - 2$

Step 1.2

Simplify the right side.

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Step 1.2.1

Simplify $3 {(- 2)}^{3} - 4$ .

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Step 1.2.1.1

Simplify each term.

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Step 1.2.1.1.1

Raise $- 2$ to the power of $3$ .

$y = 3 \cdot - 8 - 4$

$x = - 2$

Step 1.2.1.1.2

Multiply $3$ by $- 8$ .

$y = - 24 - 4$

$x = - 2$

$y = - 24 - 4$

$x = - 2$

Step 1.2.1.2

Subtract $4$ from $- 24$ .

$y = - 28$

$x = - 2$

$y = - 28$

$x = - 2$

$y = - 28$

$x = - 2$

$y = - 28$

$x = - 2$

Step 2

The solution to the system is the complete set of ordered pairs that are valid solutions.

$(- 2, - 28)$