化简求值 [(x-y^2)+(x+y)(x-y)]÷2x.

[(x-y^2)+(x+y)(x-y)]÷2x
=[x-y²+x²-y²]÷2x
=[x²+x-2y²]/2x
=(x+1)/2-y²/x ,
将 x=3 y=1.5代人上式,
原式＝(3+1)/2-1.5²/3＝2-2.25/3＝1.25.