已知-X+2Y=5,则5(X-2Y)的平方-3(X-2Y)-60的之值为( ) A 80 B 10 C 30 D40

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已知-X+2Y=5,则5(X-2Y)的平方-3(X-2Y)-60的之值为( ) A 80 B 10 C 30 D40

已知-X+2Y=5,则5(X-2Y)的平方-3(X-2Y)-60的之值为( ) A 80 B 10 C 30 D40
已知-X+2Y=5,则5(X-2Y)的平方-3(X-2Y)-60的之值为( ) A 80 B 10 C 30 D40

已知-X+2Y=5,则5(X-2Y)的平方-3(X-2Y)-60的之值为( ) A 80 B 10 C 30 D40
-X+2Y=5
所以X-2Y=-5
5(X-2Y)²-3(X-2Y)-60
=125+15-60
=80
选A

-x + 2y = 5
x - 2y = -5
5(x - 2y)² - 3(x - 2y) - 60
= 5×(-5)² - 3×(-5) - 60
= 125 + 15 - 60
= 80
所以选 A

A