Question

化简求值2(x-zy)^2-4(x-2y)+(x-2y)^2-3(x-2y),其中x=-1,y=1/2

Answer 1

化简求值2(x-zy)^2-4(x-2y)+(x-2y)^2-3(x-2y),其中x=-1,y=1/2.

2（x+2y）²-4(x-2y)+(x+2y)²-3(x-2y)

=3(x+2y)²-7(x-2y)

=3(-1+1/2x2)-7(-1-1/2x2)

=0+14

=14