4x=3y,x:y=( ):( )
3(x+y)-4(x-y)=4
(x+y/4)+(x-y/5)=3
已知y=根号下(x-4)+根号下(4-x)+3,求代数式(x-y+4xy/x-y)(x+y-4xy/x+y)?
现化简,再求值:(3x-y)(x+2y)-2(x-3y)·(x-4y),其中x=4,y=1.5
先化简在求值 (x+5y)(x+4y)-(x-y)(x+y),其中,x=-2又2/3,y=3/7
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
先化简,再求值:(x+y)(2x-y)-(x+2y)(x-2y),其中x=3,y=4.
已知x+y+2(-x-y+1)=3(1-y-x)-4(y+x-1),则x+y等于( )
解方程组:(0.2x+0.1y)/2- (4x-y)/10=(x-y)/5+ (3x+0.5y)/30 (3x+2y-1
设动点P与P'的坐标为(X,Y)(X',Y')它们满足X'=3X+2Y+1,Y'=X+4Y-3.
已知x=y+3,求代数式4分之一(x-y)的平方-0.3(x-y)+0.75(x-y)的平方+10分之3(x-y)-2(
若|x+2y-1|+y²+4y+4=0,求(2x-y)²-2(2x-y)(x+2y)+(x+2y)&