Make x the subject of the formula
x + 3 = y
This means you re-write the equation such that x woukd be on one side of the equation alone (usually the left side) and all other terms would be on the other side of the "equal to" sign.
[tex]\begin{gathered} x+3=y \\ \text{Subtract 3 from both sides} \\ x+3-3=y-3 \\ x+0=y-3 \\ x=y-3 \end{gathered}[/tex]The answer is x = y - 3
