1/6:X=15/12:3/10

1x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x+12x+13x+14x+15x=550 x-1=3x+3 x-3=12-4x 6x-14=5x-10 x+1=2-4x (x^21+x^15+x^12+x^9+x^6+x^3+1)/(x^2+x+1) 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), 计算1/[x(x+3)]+1/[(x+3)(x+6)]+.+1/[(x+15)(x+18)]=? 30-3（3-X）=4X 3X+12*6=15X+12 4X-2(50-X)=20 12(X-13)=10(X+3) 1 1x()+2x()+3x()+4x()+5x()+6x()+7x()+8x()加9x()+10x()=1980 1X?+2X?+3X?+4X?+5X?+6X?+7X?+8X?+9X?+10X?=1980求?是多少 已知 X=4- 根号3 求 (X*X*X*X-6X*X*X-2X*X+18X+23) / (X*X-8X+15)的值 求函数y=\x-1\+\x-2\+\x-3\+\x-4\+\x-5\+\x-6\+.+\x-10\的最小值 已知x=9/2 求:[(x^+7x+10)/(x^2+6x+5)]×[(x^3+1)/(x^2