SAT Math : Simplifying

Study concepts, example questions & explanations for SAT Math

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Example Questions

Example Question #2 :Binomials

If 〖(x+y)〗2= 144 and 〖(x-y)〗2= 64, what is the value of xy?

Possible Answers:

16

18

20

22

正确答案:

20

Explanation:

We first expand each binomial to get x2+ 2xy + y2= 144 and x2- 2xy + y2= 64. We then subtract the second equation from the first to find 4xy = 80. Finally, we divide each side by 4 to find xy = 20.

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