Question

Ac=4 bx=y+4 what is the value of y

Answer 1

Ac=4 bx=y+4 doesn't make sense.  Perhaps you meant Ac-4bx=y+4.  If this is not correct, ensure that you have copied down the original problem correctly.

To solve  Ac-4bx=y+4  for y, subtract 4 from both sides of this equation.  You'll get:

Ac-4bx-4 = y+4 - 4, or y = ac-4bx - 4.