Solve. $LaTeX: \displaystyle \sqrt{x + 20}=\sqrt{x + 6} + 3$

Squaring both sides gives $LaTeX: \displaystyle x + 20=x + 6 \sqrt{x + 6} + 15$ . Isolating the radical gives $LaTeX: \displaystyle \frac{5}{6}=\sqrt{x + 6}$ Squaring again gives $LaTeX: \displaystyle \frac{25}{36}=x + 6$ . Solving for $LaTeX: \displaystyle x$ gives $LaTeX: \displaystyle x=- \frac{191}{36}$ . Checking the solution, $LaTeX: \displaystyle x = - \frac{191}{36}$ , in the original equation gives $LaTeX: \displaystyle \frac{23}{6} = \frac{23}{6}$ which is true so the solution checks.