Answer:

Step-by-step explanation:
First draw a line. I will put it in an attachment so you can see the line.
Now choose to points on the line to use the slope formula.
(0,15) and (3,13).
Slope formula: 
Plug in the information needed using the two points chosen.

The slope is  .
.
Now use point-slope formula.
Point-slope formula: y-y1=m(x-x1)
y-15= (x-0)
(x-0)
y-15= x-0
x-0
Subtract 15 from both sides.
y= x-15
x-15
Hope this helps!
If not, I am sorry.