I need to know m and b

Hi Kynzie;

y+x=0

Slope-intercept form is y=mx+b.

m is the slope.

b is the y-intercept, the value of y when x=0.

y+x=0

Let's subtract x from both sides...

-x+y+x=0-x

y=-x+0

We do not need the zero, except to highlight the fact that the y-intercept is 0.

The slope is -1.

y=-x