5x+y=84,6x+3y=108 这两个方程怎么解要过程

x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 （x+y-5)*（x+y-5)+（x-y+3)=0 x*x-y*y 已知:3x-5y=0,求x/y,x-y/y,x-y/x 对于x,y定义两种运算“*”“△”如下：x*y=6x+5y,x△y=3xy,求（2*3）△4 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 3x+5y-(x+y)=6 2(x+y)-3x=-7 已知x.x+y.y-6x-8y+25=0,求3x.x+5y的值 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)= 3(x-y)把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)=3(x-y)²-4(x-y)+7(x-y)-6(x-y)²= 两道三元一次方程题（要有步骤）1.x+y=3,y+z=6,z+x=72.x-2y=4,3x-3y-2z=1,x+y+z=5 y''-5y'+6y=3x+1通解 {x+y=1 ,xy=-6{x(2x-3)=0,y=x²-1{(3x+4y-3)(3x+4y+3)=0,3x+2y=5{(x-y+2)(x+y)=0,x²+y²=8{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0 (x+y)/6+(x-y)/10=1,(x+y)/6-(x-y)/10=5 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 {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1