Find the Slope of a Parallel Line x+4y=9

$x + 4 y = 9$

Step 1

Rewrite in slope-intercept form.

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

$y = m x + b$

Subtract $x$ from both sides of the equation.

$4 y = 9 - x$

Divide each term in $4 y = 9 - x$ by $4$ and simplify.

Divide each term in $4 y = 9 - x$ by $4$ .

$\frac{4 y}{4} = \frac{9}{4} + \frac{- x}{4}$

Simplify the left side.

Cancel the common factor of $4$ .

Cancel the common factor.

$\frac{4 y}{4} = \frac{9}{4} + \frac{- x}{4}$

Divide $y$ by $1$ .

$y = \frac{9}{4} + \frac{- x}{4}$

Simplify the right side.

Move the negative in front of the fraction.

$y = \frac{9}{4} - \frac{x}{4}$

Write in $y = m x + b$ form.

Reorder $\frac{9}{4}$ and $- \frac{x}{4}$ .

$y = - \frac{x}{4} + \frac{9}{4}$

Reorder terms.

$y = - (\frac{1}{4} x) + \frac{9}{4}$

Remove parentheses.

$y = - \frac{1}{4} x + \frac{9}{4}$

Step 2

Using the slope-intercept form, the slope is $- \frac{1}{4}$ .

$m = - \frac{1}{4}$

Step 3

All lines that are parallel to $y = - \frac{1}{4} x + \frac{9}{4}$ have the same slope of $- \frac{1}{4}$ .

$m_{parallel} = - \frac{1}{4}$

Step 4