6.45-3(2+x)=9

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), 解方程】(x+8)/(x-3)-(x-9)/(x-4)=(x+7)/(x+8)-(x+2)/(x+3) 解方程：（x-8）/(x-3)-(x-9)/(x-4)=(x+7)/(x+8)-(x+2)/(x+3) x+2/x+3－x+1/x+2=x+8/x+9－x+7/x+8 解方程:(x+3)/(x+2)-(x+5)/(x+4)=(x+7)/(x+6)-(x+9)/(x+8) （1） 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) 2x/x^2-9=x-1/x^2-6x+9-1/x+3 1.x/9+x=62.x/x+1 + x+1/2x = 3 (x-2)(x2-6x-9)-x(x-5)(x-3)其中x= -1/3