求(-3x²-4y)-(2x²-5y+6)+(x²-5y-1)的值,其中X,Y满足丨x-y+1丨+(x-5)²=0
问题描述:
求(-3x²-4y)-(2x²-5y+6)+(x²-5y-1)的值,其中X,Y满足丨x-y+1丨+(x-5)²=0
答
丨x-y+1丨+(x-5)²=0x-5=0 x=5x-y+1=0y=x+1=5+1=6(-3x²-4y)-(2x²-5y+6)+(x²-5y-1)=-3x²-4y-2x²+5y-6+x²-5y-1=(x²-3x²-2x²)+(5y-5y-4y)-(6+1)=-4x²-4y...