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Mathematics>Standard Multiple Choice

Read the following SAT test question and then click on a button to select your answer.

If square root (x-a) = square root (x + b), which of the following must be true?

(A) a = 0
(B) b = 0
(C) a + b = 0
(D) a-b = 0
(E) (a^2) + (b^2) = 0

答案和解析

答案：C

解析：

Squaring both sides of the equation square root (x-a) = square root (x + b) gives the equation x-a = x + b. Subtracting x from both sides now gives -a = b, or a + b = 0.