If n^2 = m^2, which of the following must be true?  Choose the correct answer:	A) n = m	B) n = -m	C) n = |m|	D) |n| = |m|	E) n = -|m|
Solution:   We are given that n^2 = m^2, and we can start by simplifying the equation by taking the square root of both sides.   √n^2 = √m^2   When we take the square root of a variable squared, the result is the absolute value of that variable. Thus:   √n^2 = √m^2 is |n| = |m|   Note that answer choices A through D could all be true, but each of them would be true only under specific circumstances. Answer choice E is the only one that is universally true.   Answer: |n| = |m|
<result>D</result>
If n^2 = m^2, which of the following must be true?