To begin, let's take a relatively simple example.
Make x the subject of the formula:
4y + 2 = x - 4.
x = 4y + 6.
Make y the subject of the formula.
2y/5 - 3x = 2.
TIP: Remember to put brackets around 2 + 3x because both the 2 and the 3x are being multiplied by 5.
y = 5 + 15x/2.