X+0.12x+(18-x)( 1+10%)=20

（X-X*20%-18-（X-X*20%-18）*10%=X*1/2-3（过程) 解方程(x/x(x+2))+(x/(x+2)(x+4))+.+x/(x+8)(x+10)=1 X+1-3X=5X+10 6-3X=5X-20 x/2+x/8+x/12+x/20=1 x(x-1)=18 x+3/20x=46 ,x-1/5x=40 ,x-1/2x=3/4 ,x-0.2x=18解方程 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 x-10=4(x-28) 3(x-28)=x+56+28 2(1.5x-30-20)=x 2(2x-20-45)=x-1 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), 计算1/[x(x+3)]+1/[(x+3)(x+6)]+.+1/[(x+15)(x+18)]=? x/2+x/6+x/12+x/20+x/30+x/42=1 1x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x+12x+13x+14x+15x=550