How do you find the slope and slope intercept form for x+y=-5?

Apr 7, 2015

The linear equation x + y = -5 is in a nice "general" form sometimes referred to as Standard Form: Ax + By = C. You can find the slope by doing one of two different things:

1. Solve for y = (put the equation into slope-intercept form) or
2. Use a "formula"

If you actually solve the Standard Form itself for y = ...
Ax + By = C
(subtract Ax from both sides)

By = -Ax + C
(divide both sides by B)

$\frac{B y}{B} = \frac{- A x + C}{B}$

$y = \frac{- A x}{B} + \frac{C}{B}$ ...you might recognize that $- \frac{A}{B}$ is the multiplier on x, and thus, the slope equals that number!

So, the slope for your equation x + y = -5 would be $\frac{- 1}{1}$ = -1.

This is the same way that you would put your equation into slope-intercept form:
$x + y = - 5$ (subtract x from both sides)
$y = - x + - 5$
which helps you to identify both the slope (-1) and the y-intercept (-5).