x-0.8x=9 0.5x-2=24 2x-6.8=3.5 3x-2.8=2 5x-3.9=5.1

x+2x+3x+4x+5x+6x+7x+8x+9x=9x-8x-7x-6x-5x-4x-3x-2x-x.x等于多少? x^5+x^4 = (x^3-x)(x^2+x+1)+x^2+x 解方程x/(x-2)=2x/(x-3)+(1-x)/(x-5x+6) 2x+3x+4x+5x+x+6x+7x=100 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+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) 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 解方程：(x-2)(x^2-6x-9)=x(x-5)(x-3) (x-2)(x2-6x-9)-x(x-5)(x-3)其中x= -1/3