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问题: 化简求值

已知X²+y²+8x+6y+25=0,求x²-4y²/x²+4xy+4y²-x/x+2y

解答:

已知:x^+y^+8x+6y+25=0,求(x^-4y^)/(x^+4xy+4y^)-x/(x+2y)

x^+y^+8x+6y+25=(x+4)^+(y+3)^=0--->x=-4,y=-3

(x^-4y^)/(x^+4xy+4y^)-x/(x+2y)
=(x-2y)(x+2y)/(x+2y)^-x/(x+2y)
=(x-2y)/(x+2y)-x/(x+2y)
=(-2y)/(x+2y)
=6/(-10)
=-0.6