Question

已知|x+2|+2(y-1/2)^2=0.求代数式3y^2-6x^2y-4y^2+2x^2y的值

Answer 1

∵|x+2|≥0,(y-1/2)^2≥0,且|x+2|+2(y-1/2)^2=0

∴x+2=0,y-1/2=0 ==>x=-2,y=1/2

故3y^2-6x^2y-4y^2+2x^2y=-4x^2y-y^2

=-4(-2)^2*(1/2)-(1/2)^2

=8-1/4

=31/4.