Square root of 5u+2 = square root of 3u+14

Sqrt(5u + 2) = sqrt(3u + 14)
Square both sides to clear the square root.
5u + 2 = 3u + 14
subtract 3u from both siides
2u + 2 = 14
subtract 2 from both sides
2u = 12
divide both sides by 2
u = 6
When you square a square root you MUST check the solution.
sqrt(5*6 + 2) = sqrt(3*6 + 14)
sqrt(32) = sqrt(32)

The correct answer will be d. -4