Equation of a line is in the form y = mx+c, where m is the gradient and c is the y-intercept.
First step is to find the gradient.
m = (y2-y1)/(x2-x1)
= ( 5- -8)/(8-4) = 13/4
We have y = (13/4)x + c
Now we replace one of the coordinates to find c. Let’s replace (4,-8)
We have: -8 = (13/4)*4 + c
-8=13+c
c=-8-13= -21
Therefore, equation of line is:
y = (13/4)x - 21