y=(2-3x)/(x+1)=5/（x+1）-3 .等于吗,

(x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) （2x+y-1)(2x-y+1)-(3x+y)(3x-y),其中x=5分之1, 函数,y=3x/(x^2+x+1) ,x 函数y=3x/(x^2+x+1) （x 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 xy²/(x²y-y) × x²/(x²+x)=(x²-3x)/(x²-5x) × 2x-10/(x²-6x+9)=化简求植x²-1/(x²-x-2)除以x/2x-4,其中x=1/2[x-x/(x+1)]除以[x/(2x-4)] ,其中x=√2+1 x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x (x+2y)(x-2y)-(2x-y)的平方+(3x-y)(2x-5y)其中x=-1 y=13分之1 {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 化简 求值 x-{-5x-[-y+（-x+3y）+x]},其中x=-1,y=-2； 3x(2x＋y)－2x(x-y),其中x＝1,y=1/5 用递归法求y=x-(x*x*x/3!)+(x*x*x*x*x/5!)-(x*x*x*x*x*x*x/7!)+. (3x-y)^2+(3x+y)(3x-y),x=1,y=-2 x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2