Question

How do I do this question

Answer 1

To make the x the subject of an equation simply isolate x. To isolate means to get (something) by itself. To isolate x in this equation, just subtract A from both sides.

Note: Whatever operation you apply to an equation, you must apply to both sides of the equation to keep the sides equal. That is why you must subtract A from both sides.

      y = x + A
    -A        - A
y - A = x
      x = y - A

Answer:
x = y - A