1.先化简,再求值:(2X+Y)^2-(2X-Y)(X+Y)-2(X-2Y)(X+2Y),其中X=0.5,Y=-2
问题描述：
1.先化简,再求值:(2X+Y)^2-(2X-Y)(X+Y)-2(X-2Y)(X+2Y),其中X=0.5,Y=-2
2.已知X^2+Y^2-2X+2Y=-2,求代数值X^2008+Y^2009的值
3.A-(A^2B-2A^3B^2)\AB
4.0.5^(-1)-4*(-2)^(-2)+0.5^0-2^(-1)
答
1.先化简,再求值:(2X+Y)^2-(2X-Y)(X+Y)-2(X-2Y)(X+2Y),其中X=0.5,Y=-2原式=4x^2+4xy+y^2-(2x^2+2xy-xy-y^2)-2(x^2-4y^2)=3xy+10y^2=3*0.5*(-2)+10*(-2)^2=-3+40=372.已知X^2+Y^2-2X+2Y=-2,求代数值X^2008+Y^2009的值...