(1) {3x-y=5 {5y-1=3x+5 (2) {2x>1-x {x+21+2x {3x+2

先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 y=(x-1)(x-2)(x-3)(x-4)(x-5)(x-6)(x-7)(x-8)(x-9)(x-10)的导数在x=1 已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-( 求函数y=\x-1\+\x-2\+\x-3\+\x-4\+\x-5\+\x-6\+.+\x-10\的最小值 （2x+y-1)(2x-y+1)-(3x+y)(3x-y),其中x=5分之1, 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 函数,y=3x/(x^2+x+1) ,x 函数y=3x/(x^2+x+1) （x 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) x^5+x^4 = (x^3-x)(x^2+x+1)+x^2+x （x+2)(x+3) (x-4)(x+1) (y+4)(y-2) (y-5)(y-3)