先化简,再求值:当x=-六分之一,y=1时 (3x^2y-7xy^2)/6xy-(15x^2-10x)/10x-(9y^
当x=-1/3时,【十万火急!】化简求值:(9x^2y-6xy^2)÷(-3xy)-【(4y^2-9x^2)/(-3x+
先化简,再求值3x^3-[x^3+(6xy-7x)+2(x^3-3xy-4y)],其中x=-1,y=2
先化简,再求值:[-xy/(x-y)^2]^4*(x^2-xy/x)3*x^4/y^10÷(x/xy-y^2)^5
先化简,再求值:(6x-2y)*3/2xy^2-(xy-3)(xy+1)-(3x-4y)(3x+4y)+(2x-1/2y
先化简,再求值(x-y/x+y)^2÷(y-x/x^2+2xy+y^2)^2*1/x+y,其中x=-4,y=1
先化简,再求值(3xy)*(-2/3x^2y)+3x(x^2y^2)^2-(-x^4-3)*xy^4,其中,x=-1,y
先化简,再求值:3x平方y-【2x平方y-3(2xy-x平方y)-xy】,其中x=负1,y=负2
先化简,再求值 ⒈2(Xy+Xy)-3(Xy-xy)-4Xy,其中X=1,y=-1
先化简,再求值[x(x^2y^2-xy)-y(x^2+x^3y)]/3x,其中x=1,y=-1/2
(-3xy-7y)+[4x-3(xy+y-2x)],其中xy=-2,x-y=3,先化简,再求值.
先化简,再求值:{xy(x²-3y)+3xy²}(-2xy)+x³y²(2x-y
(x+2y-3xy)-(-2x-y+xy),其中x+y=,xy=-,求值.