The goal of simplifying expressions with square roots is to factor the radicand into a product of two numbers. One of these two numbers must be a perfect square. When you take the square root of this perfect square, you will get a rational number.
So let's list the factors of 52
Factors:
1, 2, 4, 13, 26, 52
Notice how 4 is the largest perfect square, so lets factor 52 into 4*13
Factor 52 into 4*13
Break up the square roots using the identity
Take the square root of the perfect square 4 to get 2
So the expression simplifies to
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Check:
Notice if we evaluate the square root of 52 with a calculator we get