-3xy.(-2x²).(1/3x²y)²
计算3x[xy-2x(1/y-x/3]+3y(x²-y²)
下列多项式:(1)x²+xy-y²;(2)-x²+2xy-y²;(3)xy+x&
若x=1/2,y=1 求x(x²+xy+y²)-y(x²+xy+y²)+3xy(
化简求值3x²y-[2xy-2(xy-3/2x²y)+xy]+3xy²其中x=3、y=-1
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
(2x²y-3xy²)-3(x²y-2xy²)+2(x²y-4xy
1/x+1/y=5,求2x-3xy+2y/x²+xy+y的值
先化简,再求值:{xy(x²-3y)+3xy²}(-2xy)+x³y²(2x-y
已知x+y=3 xy=-5 求x设abc=1 求x²+3xy+2y²/x²y+2xy
已知2X-3√xy-2y=0(x>0)求2x²+xy-9y²分之x²+4xy-16y
化简求值[1-(2x/x+y)]÷ (x²-2xy+y²/3x+3y)+(x²+xy/x&
化简 (x+y)(x²-xy+y²) ; 3(2x-1)(x+6)-5(x-3)(x+6)