X-4Y+6=9;3X-(3/4Y)+6=?

81/8*(-x-y)^6*(x-y)^3*4/9(x+y)^4*(y-x)^2 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 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 （x+y）/2- x-y/2=6 3(x+y)=4(x-y) x+y/3+x-y/2=6 4(x+y)-2(x-y)=40 解二元一次方程 {3(x+y)-4(x-y)=-9 x+y/2+x-y/6=1 解方程组：{4/x+y+6/x-y=3 9/x-y-1/x+y=1} 解方程组{4/x+y+6/x-y=3, 9/x-y-1/x+y=1 谁会解10x+y=6(x+y)+3 10y+x=4(x+y)+9 常微分方程的通解dy/dx=(x-y+1)/(x+y-3)y^4=2y^n+y=0y''+6y'+9y=e^(-3x)y''+y'-2y=4e^(2x) 若(-x+6):(x-y):(4x+y)=3:14:1,求x+y 若(-x+6):(x-y):(4x+y)=3:14:1,求x+y (-x+6):(x-y);(4x+y)=3;14:1,求x+y的值. 解二元一次方程组：3(x+y)-4(x-y)=4,x+y/2+x-y/6+1x+y/2+x-y/6+1=1 [6(x-y)的3次方*(x+y)的4次方-9*(x-y)的平方*(x+y)的3次方]根号[3(x-y)(x+y)] (x-y)的4次方/(y-x)的3次方+(x-y)0的次方*(y-x)+(-x-y)7次方/(x+y)6次方=