1/4x+120=2/5x

x^5+x^4 = (x^3-x)(x^2+x+1)+x^2+x 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1+x+x^2+x^3=0,求x+x^2+x^3+x^4+x^5+x^6+x^7+x^8的值 设函数f(x)=(x-1)(x-2)(x-3)(x-4)(x-5)(x-6)(x-7)(x-8)(x-9)(x-10), (4x+2)/x+(4x-22)/(x-5)=(x-6)/(x-4)+(7x+9)/(x+1) （1） x-3/x-2 - x-5/x-4=x-7/x-6 - x-9/x-8 1x+2x+3x+4x+5x+6x+7x…+99x=100 (X+2)/(X+1)-(X+4)/(X+3)=(X+6)/(X+5)-(X+8)/(X+7) 解方程：2x+4x+6x...+100x=1-(x+3x+5x+...+99x) 解方程 x+2/x+1+x+8/x+7=x+6/x+5+x+4/x+3 (x-1)(x-2)(x-3)(x-4)=(x+5)(x+6)(x+7)求X等于几? x+2/3x=60 x-3/5x=120 4x+18x=1