1.4/5÷x＝8 2.(1－7/9)x＝2/15 3.3/4x－1/3x＝5/12

1.4/5÷x＝8 2.(1－7/9)x＝2/15 3.3/4x－1/3x＝5/12 1x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x+12x+13x+14x+15x=550 |X-1|+|X-2|+|X-3|+|X-4|+|X-5|+|X-6|+|X-7|+|X-8|+|X-9|+|X-10| 方程x+1x+2+x+8x+9＝x+2x+3+x+7x+8 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), （1） x-3/x-2 - x-5/x-4=x-7/x-6 - x-9/x-8 x(2x－1)＝-3x(x+1)+5x²+3 1x()+2x()+3x()+4x()+5x()+6x()+7x()+8x()加9x()+10x()=1980 (x+1)(x+2)(x+3)(x+4)(x+5)(x+6)(x+7)(x+8)(x+9)(x+10)请化简 1X?+2X?+3X?+4X?+5X?+6X?+7X?+8X?+9X?+10X?=1980求?是多少 x+2x+3x+4x+5x+6x+7x+8x+9x=9x-8x-7x-6x-5x-4x-3x-2x-x.x等于多少?