m^5n^5-2n^3m^3 mn(请快速回答问题,

问题描述:

m^5n^5-2n^3m^3 mn(请快速回答问题,
x+y=0.x+3y=1,求3x^2+12xy+12y^2

3X^2+12xy+12y^2
=X^2+4xy+4y^2
=(X+2y)^2(1)
由x+3y=1和x+y=0.2得
y=0.4 x=-0.2带入(1)中得
(x+2y)^2=0.36