2xy-2分之1(4xy-8x^2y^2)+2(3xy-5x^2y^2),其中x=2分之3,y=-3分之2
=2xy-2xy+4x²y²+6xy-10x²y²
=6xy-6x²y²
=6xy(1-xy)
=6(3/2)(-2/3)[1-(3/2)(-2/3)]
=-6[1+1]
=-12