原式=xy²+1/2xy²-5x²y+2/3x²y
=3/2xy²-13/3x²y23a^2bc+10abc^2-15abc^2+2a^2bc+abc^原式=23a^2bc+2a^2bc+10abc^2+abc^2-15abc^2=25a^2bc-4abc^2先化简再求值by^2-12y-3+10y-2-by^2,其中y=-5/6原式=-12y+10y-3-2=-2y-5y=-5/6原式=-2×（-5/6）-5=5/3-15/3=-10/34a^4-2ab^3+6ab^3-3a^4,其中a=3,b=-2原式=a^4+4ab^3=a(a^3+4b^3)a=3,b=-2原式=3×（27-32）=-15另外请不要追问了，题目的处理请随意！