Question

Evaluate $\dfrac{2\sqrt{72}}{\sqrt{8}+\sqrt{2}}$.

Answer 1

Answer:  4

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Work Shown:

$\frac{2\sqrt{72}}{\sqrt{8}+\sqrt{2}}\\\\\frac{2\sqrt{36*2}}{\sqrt{4*2}+\sqrt{2}}\\\\\frac{2\sqrt{36}*\sqrt{2}}{\sqrt{4}*\sqrt{2}+\sqrt{2}}\\\\\frac{2*6*\sqrt{2}}{2*\sqrt{2}+\sqrt{2}}\\\\\frac{12\sqrt{2}}{2\sqrt{2}+\sqrt{2}}\\\\\frac{12\sqrt{2}}{3\sqrt{2}}\\\\\frac{12}{3}\\\\4$

Note in step 2, I factored each number in the square root to pull out the largest perfect square factor. From there, I used the rule that $\sqrt{A*B} = \sqrt{A}*\sqrt{B}$ to break up the roots.