m1 x m2 = - 1
Rearrange 4x + 2y = 8.
4x + 2y = 8
-4x, then ÷ 2
y = - 4x + 8 / 2
y = - 2x + 4
m1 = - 2, find reciprocal of - 2, by placing 1 over the 2
So, - 2 will become - 1/2, but multiplying this gives us a positive 1. Thus, m2 = 1/2
m1 x m2 = - 1
-2 x 1/2 = - 1
That means slope perpendicular to the line
4x + 2y = 8 is y = 1/2x, where a half is the gradient/slope.
Ans: 1/2
Hope this helps!