化简xy/[(100-x)*8]=3/20
化简xy/[(100-x)*8]=3/20
化简:xy分之3x^2+2xy-xy分之2x^2-xy=
(8xy-3x平方)-5xy-2(3xy-2x平方),其中,x=2,y=-1
x+y=8,xy=-2,求(5xy+4x+7y)+(6x-3xy)-(4xy-3y)的值
已知2x+xy=10,3y+2xy=6.求4x+8xy+9y=?
2x平方-3xy+(2xy-x平方)化简!
xy/3x+2y=1/8 xy/2x+3y=1/7
解方程组xy+x=16&xy-x=8
(-3x^y+2xy)-( )=4x^+xy
已知A=8x^2y-6xy^2-3xy,B=7xy^2-2xy+5x^2y,
由已知x+y=-2,xy=3那么2(x+xy)-[(xy-3y)-x]-(-xy)等于多少?
先化简,再求值 ⒈2(Xy+Xy)-3(Xy-xy)-4Xy,其中X=1,y=-1