Answer
{$-3\sqrt 5,3\sqrt 5$}
Work Step by Step
Using Property 10.1, which says that for any non-negative real number $a$, $x^{2}=a$ can be written as $x=\pm\sqrt a$, we obtain:
Step 1: $y^{2}=45$
Step 2: $y=\pm \sqrt {45}$
Step 3: $y=\pm \sqrt {9\times5}$
Step 4: $y=\pm (\sqrt 9\times\sqrt 5)$
Step 5: $y=\pm (3\times\sqrt 5)$
Step 6: $y=\pm (3\sqrt 5)$
Step 7: $y=3\sqrt 5$ or $y=-3\sqrt 5$
The solution set is {$-3\sqrt 5,3\sqrt 5$}.
