5x^y-[2x^2y-3(xy^2-2x^2y+2xy^2)],其中x,y满足|x-1|+(y+2)^2=0先化简,再求值如果及时还给悬赏!急!
问题描述：
5x^y-[2x^2y-3(xy^2-2x^2y+2xy^2)],其中x,y满足|x-1|+(y+2)^2=0
先化简,再求值
如果及时还给悬赏!急!
答
∵|x-1|+(y+2)^2=0
∴x-1=0 x=1 y+2=0 y=-2
5x^y-[2x^2y-3(xy^2-2x^2y+2xy^2)]
=5x^y-[2x²y－3(3xy²-2x²y)]
＝5x^y-[2x²y－9xy²＋6x²y]
＝5x^y-[8x²y－9xy²]
＝5x^y-8x²y＋9xy²
＝5×1^﹙－2﹚－8×1²×﹙-2﹚＋9×1×﹙-2﹚²
＝5+16+36
＝57
答
5x^y-[2x^2y-3(xy^2-2x^2y+2xy^2)]
=5x^y-[2x^2y-3xy^2+6x^2y-6xy^2]
=5x^y-2x^2y+3xy^2-6x^2y+6xy^2
=5x^y-8x^2y+9xy^2
|x-1|+(y+2)^2=0
所以 x-1=0 y+2=0
x=1 y=-2
代入上式得 5*1^-2-8*(-2)+9*(-2)^2
=5+16+36
=21+36
=57