Question

当x+2的绝对值+（y-3)的平方=0时求代数式3x-y的平方+(4y的平方-xy)-2(x-xy)的值

Answer 1

∵|x+2|+(y-3)^2=0

∴x=-2,y=3

原式=3x-y^2+(4y^2-xy)-2(x-xy)

=3x-y^2+4y^2-xy-2x+2xy

=3y^2+xy+x

=27-6-2

=19