6x-7y/2x+3y 还可不可以化简

化简求值：(7x-2y)(3x-2y-1)-(4x+3y)(9x+6y),其中x=2,y=-1 化简下列各式,并求值:3(x-y)²-7(x-y)+8(x-y)²+6(x-y) 其中x=2,y 求根下y分之x加2加x分之y减根下y分之x-2+x分之y可不可以化简.老师说要化简呀,好像是用因式分解. 化简求值 -3(2x-y)-｛7x-〔6x+2x-(10x-8y)〕-x-2(3x-4y)｝ 2(y-x)的平方-7(x-y)+6(x-y)-3(y-x)的平方 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 计算：(x-y)^7÷(y-x)^6+(-x-y)^3÷(x+y)^2 x^8-x^7y+x^6y^2-x^5y^3+x^4y^4-x^3y^5+x^2y^-xy^7+y^8 化简求值:(x+y)-(2x+1/2y)-(3x+1/6y)-(4x+1/12y)-(5x+1/20y)-.(10x+1 3(x-y)-2(x+y)-5(x-y)+4(x+y)+3(x-y) 化简合并同类项 1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) 化简分式方程:x*x-xy-y*y/x*x-3x-6y+2xy