（Y-2）/3=X(Y-4)/5=X(Y-6)/7=X(Y-8)/9=XY/11=X求Y和X是多少?方程.我没学过.我自己乱写的.真正题目如下：说一个屋里有多个桌子,有多个人?如果3个人一桌,多2个人.如果5个人一桌,多4个人.如果7个人一桌,

3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 （x+y）/2- x-y/2=6 3(x+y)=4(x-y) 先化简再求值(x-y)(x-2y)+(x-2y)(x-3y)-2(x-3y)(x-4y) x=4 y=5 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 x+2y=3（x+y）+5 3x-4y=4（x+y）-15 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 y'=（y/x）^2+y/x+4微分方程 若3x-5y=0,则x+y/x=（）,x-y/y=（）,2x-3y/2x+3y=( ) 已知（x+y）2 =2,(x-y)3 =3,求(x+y)7(x-y)2(x+y)3(y-x)4 的值 若x+y=4,则多项式1/2(x+y)+4(x-y)-3（x-y）-3/2(x+y)-x+y值是（） .先化简再求值：（2x+y）（2x+y)-(2x-y)平方其中X,Y满足X平方+Y平方-2X+4Y+5=0 若x-y分之x+y=3,求式子x+y分之5(x-y)—2（x-y）分之x+y的值 (x-2y)^5=a0(x+2y)^5+a1(x+2y)^4*y+a2(x+2y)^3*y^2+a3(x+2y)^2*y^3+a4(x+2y)y^4+a