Question

Someone please help explain how to do this

Answer 1

Answer: $3*\sqrt{5}$
Note: if you are typing it out on the keyboard, you'd write 3*sqrt(5)
sqrt is shorthand for "square root"

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Factor 45 so that one of the factors is a perfect square and this factor is the largest perfect square possible
Then you break up the root like so
$\sqrt{45}=\sqrt{9*5}$
$\sqrt{45}=\sqrt{9}*\sqrt{5}$
$\sqrt{45}=3*\sqrt{5}$