Verified Answer :

Gradient, m=\(\frac{change in y}{change in x}\)
m=\(\frac{8-5}{-1-2}\)
m=\(\frac{3}{-3}\)
m=-1
y=-x+c
Replacing for x and y using point (2, 5)
5=-(2)+c
5+2=c
c=7
y=-x+7

First, find the slope:    = m=y2-y1/x2-x1
=8-5/2+1
3/3
=1


Use either point:  (2,5)
Remember the form:  y - y1 = m ( x - x1)
Substitute:  y - 5 = 1 ( x - 2)
                  y - 5 = (x -2)  Ans.