Answer
$y=5\pm2\sqrt{7}$
Work Step by Step
Using the completing the square method, the solutions of the given quadratic equation, $
y^2-10y=3
,$ is
\begin{array}{l}\require{cancel}
y^2-10y+\left( \dfrac{-10}{2} \right)^2=3+\left( \dfrac{-10}{2} \right)^2
\\\\
y^2-10y+25=3+25
\\\\
(y-5)^2=28
\\\\
y-5=\pm\sqrt{28}
\\\\
y-5=\pm\sqrt{4\cdot7}
\\\\
y-5=\pm\sqrt{(2)^2\cdot7}
\\\\
y-5=\pm2\sqrt{7}
\\\\
y=5\pm2\sqrt{7}
.\end{array}
