X+y=4,Xy=-12 求(1)XxX+yxy (2)XxXxy+Xxyxy

问题描述:

X+y=4,Xy=-12 求(1)XxX+yxy (2)XxXxy+Xxyxy

(1)XxX+yxy
=(x+y)^2-2xy
=4^2+2*12
=16+28
=44

(2)XxXxy+Xxyxy
=xy*(x+y)
=4*(-12)
=-48

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