6x+5Y=31 2X+3Y=17
6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2=
那6X+5Y=31 2X+3Y=17 6x-2y+y-y=13-7?
先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y
{3x-2y=3,2x+2y=17 {4x-2y=14,5x+y=7 {x+3y=6,2x-3y=3 {2x+3y=11
x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20
{(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20
4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于