Find the Equation Using Point-Slope Formula (-5,-1) , (5,2)

$(- 5, - 1)$ , $(5, 2)$

Step 1

Find the slope of the line between $(- 5, - 1)$ and $(5, 2)$ using $m = \frac{y_{2} - y_{1}}{x_{2} - x_{1}}$ , which is the change of $y$ over the change of $x$ .

Slope is equal to the change in $y$ over the change in $x$ , or rise over run.

$m = \frac{change in y}{change in x}$

The change in $x$ is equal to the difference in x-coordinates (also called run), and the change in $y$ is equal to the difference in y-coordinates (also called rise).

$m = \frac{y_{2} - y_{1}}{x_{2} - x_{1}}$

Substitute in the values of $x$ and $y$ into the equation to find the slope.

$m = \frac{2 - (- 1)}{5 - (- 5)}$

Simplify.

Simplify the numerator.

Multiply $- 1$ by $- 1$ .

$m = \frac{2 + 1}{5 - (- 5)}$

Add $2$ and $1$ .

$m = \frac{3}{5 - (- 5)}$

Simplify the denominator.

Multiply $- 1$ by $- 5$ .

$m = \frac{3}{5 + 5}$

Add $5$ and $5$ .

$m = \frac{3}{10}$

Step 2

Use the slope $\frac{3}{10}$ and a given point $(- 5, - 1)$ to substitute for $x_{1}$ and $y_{1}$ in the point-slope form $y - y_{1} = m (x - x_{1})$ , which is derived from the slope equation $m = \frac{y_{2} - y_{1}}{x_{2} - x_{1}}$ .

$y - (- 1) = \frac{3}{10} \cdot (x - (- 5))$

Step 3

Simplify the equation and keep it in point-slope form.

$y + 1 = \frac{3}{10} \cdot (x + 5)$

Step 4

Solve for $y$ .

Simplify $\frac{3}{10} \cdot (x + 5)$ .

Rewrite.

$y + 1 = 0 + 0 + \frac{3}{10} \cdot (x + 5)$

Simplify by adding zeros.

$y + 1 = \frac{3}{10} \cdot (x + 5)$

Apply the distributive property.

$y + 1 = \frac{3}{10} x + \frac{3}{10} \cdot 5$

Combine $\frac{3}{10}$ and $x$ .

$y + 1 = \frac{3 x}{10} + \frac{3}{10} \cdot 5$

Cancel the common factor of $5$ .

Factor $5$ out of $10$ .

$y + 1 = \frac{3 x}{10} + \frac{3}{5 (2)} \cdot 5$

Cancel the common factor.

$y + 1 = \frac{3 x}{10} + \frac{3}{5 \cdot 2} \cdot 5$

Rewrite the expression.

$y + 1 = \frac{3 x}{10} + \frac{3}{2}$

Move all terms not containing $y$ to the right side of the equation.

Subtract $1$ from both sides of the equation.

$y = \frac{3 x}{10} + \frac{3}{2} - 1$

To write $- 1$ as a fraction with a common denominator, multiply by $\frac{2}{2}$ .

$y = \frac{3 x}{10} + \frac{3}{2} - 1 \cdot \frac{2}{2}$

Combine $- 1$ and $\frac{2}{2}$ .

$y = \frac{3 x}{10} + \frac{3}{2} + \frac{- 1 \cdot 2}{2}$

Combine the numerators over the common denominator.

$y = \frac{3 x}{10} + \frac{3 - 1 \cdot 2}{2}$

Simplify the numerator.

Multiply $- 1$ by $2$ .

$y = \frac{3 x}{10} + \frac{3 - 2}{2}$

Subtract $2$ from $3$ .

$y = \frac{3 x}{10} + \frac{1}{2}$

Step 5

Reorder terms.

$y = \frac{3}{10} x + \frac{1}{2}$

Step 6

List the equation in different forms.

Slope-intercept form:

$y = \frac{3}{10} x + \frac{1}{2}$

Point-slope form:

$y + 1 = \frac{3}{10} \cdot (x + 5)$

Step 7

Find the Equation Using Point-Slope Formula (-5,-1) , (5,2)

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