已知x-y=-3,-x+3y=2,求代数式x2-4xy+3y2的值.
问题描述:
已知x-y=-3,-x+3y=2,求代数式x2-4xy+3y2的值.
答
∵x-y=-3,-x+3y=2,
∴原式=(x-y)(x-3y)=-(x-y)(-x+3y)=-(-3)×2=6.