[(xy+2)(xy-2)-2x^2y^2+4]/(xy),其中:x=10,y=-1/25求这道式子的值.

问题描述:

[(xy+2)(xy-2)-2x^2y^2+4]/(xy),其中:x=10,y=-1/25
求这道式子的值.

[(xy+2)(xy-2)-2x^2y^2+4]/(xy)
=[(x^2y^2-4)-2x^2y^2+4]/(xy)
=-x^2y^2/xy
=-xy
=-10*(-1/25)
=2/5