5X*0.15+9Y*0.2=0.18*(5X+9Y)
5x=3y,(2x+y)的平方=5x(x+y)+9
3x-2y=9 x-3y=2 x+y=5 x+2y=3 y=x 2x+y=8
已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值
y-x=3 7x+5y=-9
3x-3y=9 x+y=5
5x-y=110 9y-x=110
{y=x+3,7x+5y+9;
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
解方程组:2/(x+y)+5/(x-y)=18 9/(x+y)-10/(y-x)=66
解方程组:2/(x+y)+5/(x-y)=18 9/(x+y)-10/(y-x)=66
解方程组x:y=2:3和5x+3y=38 3y+x/y=8和9y-2x/y=9
解方程组: {3x+2y=13 3x-2y=5 {x-y/3=x+y/2+1 2x-5y=9