{4x+9y=13 2x+5y=7

3x+2=y 5X+4=Y 7X+6=Y 9X+8=y 11x=y要如何计算 3x+2=y 5x+4=y 7x+6=y 9x+8=y 11x=y y-3x=2,y-5x=4,y-7x=6,y-9x=8,y-11x=0方程组, 3x+2=y 5x+4=y 7x+6=y 9x+8=y 11x=y 联立方程 有的话 用代入法 1,x-y=4 4x+2y=-1 2,x-y=13 x=6y-7 3,5x-y=110 9y-x=110 已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值 2X+Y+Z=10,X+2Y+Z=-6,X+Y+2Z=8 5X+4Y-3Y=13,2X-3Y+7Z=19,3X-Y=2X 解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7 已知4x=9y求(1)x+y/y (2)y-x/2x 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 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 已知x*x+4x+y*y-2y+5=0,则x*x+y*y=?