5×2+x（y-5）=19 & 5×2+x（1.5y-5）=31如题

已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 分式的加减:[(x/y-y/x)除以（x+y）+x（1/y-1/x)]除以1+x/y,其中x=5,y=2 先化简,再求值 [2/3x - 2/x+y（x+y/3x -x-y）]*x/x-y,其中5x+3y=0 {5(x-3y)-6=2x+1 3(x+6y)+4=9y+19 ｛3分之2（x-y）=4分之x+y-1 6）x+y)=4(2x-y)+16 若3x-5y=0,则x+y/x=（）,x-y/y=（）,2x-3y/2x+3y=( ) .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 2(x-y)=5y,x-y=-5 (5)若x/2=y/3(y不为0）则x/y=____,x+y/y=___,y/x-y=___. x-y / 5y= (y-x)^2 / ( ) x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2 解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 （x-y）^3×（y-x）^4+（x-y）^2×（y-x）^5 x*x+2x+y*y-4y+5=0 x= y= 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 {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1