Question

【（xy+2)(xy-2)-2x的2次方y的2次方+4】除（-xy),其中xy=-5/2.

Answer 1

[(xy+2)(xy-2)-2x^2y^2+4]/-xy

=[(x^2y^2-4)-2x^2y^2+4]/-xy

=(x^2y^2-4-2x^2y^2+4）/-xy

=(-x^2y^2）/-xy

=xy

=-5/2