{x+3y=5 ,3x-6y=6
6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5
【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2=
已知x.x+y.y-6x-8y+25=0,求3x.x+5y的值
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
{4/(x+y)+6/(x-y)=3 {9/(x-y)-1/(x+y)=1
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
{x=5y 3x+6y=42
x+y=3 x+2y=9 3/x+1=y y-x=3 y=2x-3 y-3x=1 2(x+1)-y=6 7x-5y=-9
x+y/2+x-y/3=5/6;x=y/6-x-y/3=1/2