How do you graph the line through point (-3,-1) and slope m=-1/5?

1 Answer
Mar 23, 2017

y=-1/5x+8/5

Explanation:

We use the point-slope formula: y-y_1=m(x-x_1)

We know:
m=-1/5
A point: (-3,-1) -> (x_1,y_1)

Thus, we substitute all these values into the point-slope formula:

y-(-1)=-1/5(x-(-3)) -> y+1=-1/5(x+3)

This gives us the equation of the line with the slope -1/5 that passes through the point (-3,-1) but if you need to write the equation in y=mx+b then here's how we do it.

So we are simply solving for y

y+1=-1/5(x+3)

y+1=-1/5x-3/5

y=-1/5x-3/5-1 -> y=-1/5x(-3/5-5/5)

y=-1/5x+8/5

We can verify this graphically: graph{-1/5x-8/5 [-10, 10, -5, 5]}