The basic form of linear function is
y=ax+b
For finding the slope, use the slope formula.
(4-2)/(-2+1)= 2/-1=-2
We first found a which is -2.
Then insert any point to find the value of b. In this case, I will insert (1,-2).
-2=-2+b
b=-2+2=0
The linear graph is y=-2x