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

Redirected from "What is an example of an Ideal gas law practice problem?"
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]}