x÷3+（100-x）×2=100这题怎么做?

x-2x+3x-4x+5x.+99x-100x=25求解 2x+3x+4x+5x+x+6x+7x=100 x+2x+3x+.+100x （X+X)+(X-X)+(X*X)+(X/X)=100 解方程：（1）2x-19=7x+31 (2)20-2x=x-1 (3)19-x=100-10x (4)1/3x+5=2/3x-62x-19=7x+317x-2x=-19-31这里应该是31+19吧？5x=-50x=-50÷5x=-10 1/X(X+1)+1/(X+1)(X+2)+1/(X+2)(X+3).+1/(X+99)(X+100)= 解方程：2x+4x+6x...+100x=1-(x+3x+5x+...+99x) 1X+2X+3X…+98X+99X+100X=50500X X等于多少? 1x+2x+3x+4x+5x+6x+7x…+99x=100 100×2x+10x+3x+216=100×3x+10×2x+x 已知：f（x）=x(x-1)(x-2)(x-3)……（x-100),求f'(5) 解方程:x-2x+3x-4x+...+99x-100x=25 解方程：x-2x+3x-4x+.+99x-100x=25 x-2x+3x-4x+...+99x-100x=25 已知x^4+x^3+x^3+x^2+x^1+1=0,求x^100+x^99+x^98+x^97+x^96的值 先化简再求值(x+3x+5x+7x+.+101x)-(2x+4x+6x+...100x),其中x=51分之2 3X+（100-X）÷2=100 3X+（100-X）÷2=100