若2x-y=5,求5（y-2x）^2-3y+6x-60的值 .

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 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 若x-y/x+y=5,求x-y/2x+2y+5x+5y/3x-3y的值 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+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值 若2x-3y=0,求5x+4y/3x-2y 若x>0,y>0,且√x(√x+√y)=3√y(√x+5√y),求2x+2√x*√y+3y/x-√x*√y+y 5X+Y=3 X+5Y=2 求x和y.5X+Y=3X+5Y=2求x和y. 若3x-5y=0,则x+y/x=（）,x-y/y=（）,2x-3y/2x+3y=( ) 求(X+Y)(X-Y)(X²+Y²),X=5 Y=2, 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 y=x^3-5x^2+2x-8 求y^2求y撇 6x+5Y=31 2X+3Y=17求X求 Y 若x>o,y>o,且根号x(根号x+根号y)=3根号y(根号x+5根号y)求x+根号xy分之2x-根号xy-5y式子是√x（√x+√y）=3√y（√x+5√y），求x+√xy分之2x-√xy-5y 已知x:：y：z=3：4：5,(1)求x+y分之z的值；（2）若x+y+z=6,求x,y,z. 1、若x^2+y^2=5,xy=3,求(x+y)^2 （x-y）^2 2、x^+y^=5,x+y=6,求xy 3、若x+y=6,xy=3,求x^2+y^2 (x-y)^21、若x^2+y^2=5,xy=3,求(x+y)^2 （x-y）^22、x^+y^=5,x+y=6,求xy3、若x+y=6,xy=3,求x^2+y^2 (x-y)^24、a+b=5,a-b=3,求ab