1.可以看出阴影是个正方形,边长是m-n,所以面积为(m-n)^2
2.x+y=-9
(x+y)^2=81
x^2+y^2+2xy=81
x^2+y^2+2*8=81
x^2+y^2=65
x^2+y^2-2xy=65-2*8=49
(x-y)^2=49
x-y=±7
1.可以看出阴影是个正方形,边长是m-n,所以面积为(m-n)^2
2.x+y=-9
(x+y)^2=81
x^2+y^2+2xy=81
x^2+y^2+2*8=81
x^2+y^2=65
x^2+y^2-2xy=65-2*8=49
(x-y)^2=49
x-y=±7