Pre-Algebra Examples

$15 = - 3 y + 21 x$

Step 1

The slope-intercept form is $y = m x + b$ , where $m$ is the slope and $b$ is the y-intercept.

$y = m x + b$

Step 2

Rewrite in slope-intercept form.

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Step 2.1

Rewrite the equation as $- 3 y + 21 x = 15$ .

$- 3 y + 21 x = 15$

Step 2.2

Subtract $21 x$ from both sides of the equation.

$- 3 y = 15 - 21 x$

Step 2.3

Divide each term in $- 3 y = 15 - 21 x$ by $- 3$ and simplify.

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Step 2.3.1

Divide each term in $- 3 y = 15 - 21 x$ by $- 3$ .

$\frac{- 3 y}{- 3} = \frac{15}{- 3} + \frac{- 21 x}{- 3}$

Step 2.3.2

Simplify the left side.

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Step 2.3.2.1

Cancel the common factor of $- 3$ .

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Step 2.3.2.1.1

Cancel the common factor.

$\frac{- 3 y}{- 3} = \frac{15}{- 3} + \frac{- 21 x}{- 3}$

Step 2.3.2.1.2

Divide $y$ by $1$ .

$y = \frac{15}{- 3} + \frac{- 21 x}{- 3}$

Step 2.3.3

Simplify the right side.

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Step 2.3.3.1

Simplify each term.

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Step 2.3.3.1.1

Divide $15$ by $- 3$ .

$y = - 5 + \frac{- 21 x}{- 3}$

Step 2.3.3.1.2

Cancel the common factor of $- 21$ and $- 3$ .

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Step 2.3.3.1.2.1

Factor $- 3$ out of $- 21 x$ .

$y = - 5 + \frac{- 3 (7 x)}{- 3}$

Step 2.3.3.1.2.2

Cancel the common factors.

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Step 2.3.3.1.2.2.1

Factor $- 3$ out of $- 3$ .

$y = - 5 + \frac{- 3 (7 x)}{- 3 (1)}$

Step 2.3.3.1.2.2.2

Cancel the common factor.

$y = - 5 + \frac{- 3 (7 x)}{- 3 \cdot 1}$

Step 2.3.3.1.2.2.3

Rewrite the expression.

$y = - 5 + \frac{7 x}{1}$

Step 2.3.3.1.2.2.4

Divide $7 x$ by $1$ .

$y = - 5 + 7 x$

Step 2.4

Reorder $- 5$ and $7 x$ .

$y = 7 x - 5$