If 2m/y = (a² + b²)/ab, then √(m + y)/√(m − y) = ?

Correct answer: d (a + b)/(a − b)

From m/y = (a² + b²)/2ab, (m + y)/(m − y) = (a + b)²/(a − b)²; the root gives (a + b)/(a − b).

Why the other options are wrong

• a (a + b)²/(a − b)²: The root was not taken; (m + y)/(m − y) = (a + b)²/(a − b)², and the question has a square root.
• b (a − b)²/(a + b)²: This is inverted and has no root; the result is (a + b)/(a − b).
• c (a − b)/(a + b): This is inverted; m + y is in the numerator so (a + b) goes on top.