Algebra Examples

$- 28 = - 7 (3 x + 4) + 21 x$

Step 1

Rewrite the equation as $- 7 (3 x + 4) + 21 x = - 28$ .

$- 7 (3 x + 4) + 21 x = - 28$

Step 2

Simplify $- 7 (3 x + 4) + 21 x$ .

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Step 2.1

Simplify each term.

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Step 2.1.1

Apply the distributive property.

$- 7 (3 x) - 7 \cdot 4 + 21 x = - 28$

Step 2.1.2

Multiply $3$ by $- 7$ .

$- 21 x - 7 \cdot 4 + 21 x = - 28$

Step 2.1.3

Multiply $- 7$ by $4$ .

$- 21 x - 28 + 21 x = - 28$

Step 2.2

Combine the opposite terms in $- 21 x - 28 + 21 x$ .

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Step 2.2.1

Add $- 21 x$ and $21 x$ .

$0 - 28 = - 28$

Step 2.2.2

Subtract $28$ from $0$ .

$- 28 = - 28$

Step 3

Since $- 28 = - 28$ , the equation will always be true for any value of $x$ .

All real numbers

Step 4

The result can be shown in multiple forms.

All real numbers

Interval Notation:

$(- \infty, \infty)$