解7x+9y=39
解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7
解方程组 2x+y+z=7 x+2y+z=8 x+y+2x=9
设这间屋子有x张桌子,有y个人.3x+2=y 5x+4=y 7x+6=y 9x+8=y 11x=y 如何解
解方程组(1)3x+2y=7,x-y=9,(2)3x+y=7,5x+3y=1
解方程组 (1){2x-y=5,x-2y=1 (2){7x+3y=5,-5x+6y=-9
解方程组,1、x/2=y/3 3x-5y=9 2、 x-2y=-7 3(x-2)=1-y
y-x=3 7x+5y=-9
X+Y=9 6X+7Y=59
{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.100/(X+Y)+64/(X-Y)=9;80/(X+Y)+80/(X-Y)=9
解方程一;{x+y-z=6,x-3y+2z=1,3x+2y-z=-7.②{3x+4z=7,2x+3y+z=9,5x-9y