2（0.3x+4）-5（0.2x-7）=9 x=?

（1） x-3/x-2 - x-5/x-4=x-7/x-6 - x-9/x-8 解方程：（x-8）/(x-3)-(x-9)/(x-4)=(x+7)/(x+8)-(x+2)/(x+3) x+2x+3x+4x+5x+6x+7x+8x+9x=9x-8x-7x-6x-5x-4x-3x-2x-x.x等于多少? 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 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), 5x/(x+3)(x+2)+（2x-5）/(x-4)(x+3)=（7x-70）/(x+2)(x+4) (4x+2)/x+(4x-22)/(x-5)=(x-6)/(x-4)+(7x+9)/(x+1) 解方程:(x+3)/(x+2)-(x+5)/(x+4)=(x+7)/(x+6)-(x+9)/(x+8) 解方程（x-2）X（x的平方-6x-9）=x(x-5)X(x-3) 1x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x+12x+13x+14x+15x=550 5x+3=x-4,4y+11=22,11x+68-2x=100-9x,0.1x/0.2-（0.27x+0.18）/0.0 2x+3x+4x+5x+x+6x+7x=100