Answer
$y=100$
Work Step by Step
Using the properties of equality, the given equation, $
2y^{1/2}-13=7
$, is equivalent to
\begin{array}{l}
2y^{1/2}=7+13
\\\\
2y^{1/2}=20
\\\\
y^{1/2}=\dfrac{20}{2}
\\\\
y^{1/2}=10
.\end{array}
Raising both sides to the $\text{
2nd
}$ power, the solution to the equation above, $
y^{1/2}=10
$, is
\begin{array}{l}
y=100
.\end{array}
Upon checking, $
y=100
$ satisfies the given equation.