To answer the question we make the sum on the left side of the equation:
[tex]\begin{gathered} \frac{1}{2}y+5=\frac{y+10}{2} \\ \frac{y}{2}+5=\frac{y+10}{2} \\ \frac{y}{2}+\frac{10}{2}=\frac{y+10}{2} \\ \frac{y+10}{2}=\frac{y+10}{2} \end{gathered}[/tex]
Since both sides are exactly the same. this equation is always true.
