(20+x)/(100+x)=1/2

(20+x)/(100+x)=1/2 x/2+x/8+x/12+x/20=1 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 设函数f(x)=(x-1)(x-2)...(x-100)(x>100),求F'(X) f(x)=x(x-1)(x-2)…(x-99)(x-100),求f'(100) 2x(x-1)-x(3x+2)=(-x-1)(x+6)-20 解方程X(X+1)-X(X-3)=2(X+1)(X-1)+20 x(x+1)²-x(x²-3)-2(x+1)(x-1)=20 x-2=(104-x)+2 6x-59=10x-75 (x+10)+(x-15)=280-x4（x-62)=x-38 60x-40=(60+20)*(x-5) 32x+32*0.5-25x+64x=24x+496-49x x+15=3*(109-x ) 5(3x-1.4)=2(6x-0.5) 3(x+0.9)=5(x-1.7) 13x-4(2x+5)=17(x-2)-4(2x-1) (13x+8)/3=5x-1x-60=2[(3561-x)+100]+1 (x+9)+12=2[(x-9)-1 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 （X+X)+(X-X)+(X*X)+(X/X)=100 x/x-2+x-9/x-7=x+1/x-1+x-8/x-6, x/x-2+x-9/x-7=x+1/x-1+x-8/x-6, X+25%X+15%X=420 2X+150=20501.5X-1200=(1+20%)2X-5+X=100 x(x-1)(x-2)...(x-99)(x-100)