2y-3x/5=1则9x-6y=
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
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
若2x-3y+4=0则x(x*x-1)+x(5-x*x)-6y+7
{4/(x+y)+6/(x-y)=3 {9/(x-y)-1/(x+y)=1
6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
{2x-5y=21,{2x+y=6 {x-3y=1 {y=-2x+3 y=-x; y=1/2x+1 5x-9y=-13
已知x,y为实数,y=(√(x^2-9)+√(9-y^2)+1)/(x-3),则5x+6y=?
x+y/2+x-y/3=5/6;x=y/6-x-y/3=1/2
若5x+3y=3x+4y=x+2y+6,则x+y=___
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)