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(x+3y)²-2(x-y)(x+y)+(x+y)²其x=0.5,y=-2

题目详情
(x+3y)²-2(x-y)(x+y)+(x+y)²其x=0.5,y=-2
▼优质解答
答案和解析
(x+3y)²-2(x-y)(x+y)+(x+y)²其x=0.5,y=-2
原式=x²+6xy+9y²-2(x²-y²)+x²+2xy+y²
=x²+6xy+9y²-2x²+2y²+x²+2xy+y²
=12y²+8xy
=12×(-2)²+8×0.5×(-2)
=48-8
=40