(x-5)(100-7(x-7))=y
7x+[-3x-3(x-2y)]-[5x-(2x-y)]
已知5x=7y,x与y( )
(x-y)7÷(y-x)4+(-x-y)8÷(x+y)5.
(x-4y)分之(3x)+(4y-x)分之(x+y)-(x-4y)分之(7y)
已知(2y-x)/(7x-5y),则x/y的值为( )
去括号并合并同类项(1)3x-2(x+7)+2(2x+5) (2)(4x-3y)-[-(3y-x)+(x-y)]-5x
化简求值(x+5y)(x+4y)-(x-y)(x+y),其中x=一又2/5,y=-1/7
先化简在求值 (x+5y)(x+4y)-(x-y)(x+y),其中,x=-2又2/3,y=3/7
5(x-y)³-3(x-y)²+7(x-y)-5(x-y)³+(x-y)²-5(
若3x=7y,则y分之x= ,x:(x:y)=
若3x=7y,则y比x= ,x:(x+y)=
说明理由:多项式(5x的立方-7x立方y+3x平方y)+2x立方-(-7x立方y+3x平方y+7x立方)的值与x.y的值