Question

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

Answer 1

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)

`(By)/B= (-Ax+C)/B`

`y = (-Ax)/B+C/B` ...you might recognize that `-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 `(-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).