Question

I understood none of today's lesson and I need an explanation on a couple problems, the problems where you have to take an equation with multiple variables and make it so one side has a single isolated variable. Please explain these:
2m - nx = x + 4 solve for x
x/a - 1 = y/b solve for x
V=1/3 (pi) r^2 (h) solve for H
A= (f+g/2) h solve for g
I only need explanations.

Answer 1

2m - nx = x + 4

Answer 2

2m = x + 4 + nx

Answer 3

2m - 4 = x + nx

Answer 4

2m - 4 = x(1 + n)