Start with the given expression
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 112
Factors:
1, 2, 4, 7, 8, 14, 16, 28, 56, 112
Notice how 16 is the largest perfect square, so lets factor 112 into 16*7
Factor 112 into 16*7
Break up the square roots using the identity 
Take the square root of the perfect square 16 to get 4
So the expression simplifies to 
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Check:
Notice if we evaluate the square root of 112 with a calculator we get

and if we evaluate we get

This shows that . So this verifies our answer |