Question 300409
To put something under the radical you need to multiply it by itself.
For example:{{{2 = sqrt(2*2)}}} or rewritten as {{{sqrt(4)}}}.
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Now to your problem.
Given: {{{2*sqrt(2) = sqrt(U)}}}
To put the 2 under the radical you must do 2*2
{{{sqrt(2*(2*2)) = sqrt(U)}}} Simplify
{{{sqrt(8) = sqrt(U)}}} Square both sides
{{{highlight(8 = U)}}}