3(X+2.5)=5x 3x+7=5x 7=5x-3x 2x=7 x=3.5 中的7是怎么来 的

用递归法求y=x-(x*x*x/3!)+(x*x*x*x*x/5!)-(x*x*x*x*x*x*x/7!)+. 3(X+2.5)=5x 3x+7=5x 7=5x-3x 2x=7 x=3.5 中的7是怎么来 的 x+2x+3x+4x+5x+6x+7x+8x+9x=9x-8x-7x-6x-5x-4x-3x-2x-x.x等于多少? 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 已知1+x+x^2+x^3=0,求x+x^2+x^3+x^4+x^5+x^6+x^7+x^8的值 已知3x*x-x=1,求6x*x*x+7x*x-5x+2000 7x-3(2/3x+1/5x)-(x+2/5x)+2x,=5x怎么求出 (2x-1)/(x-1)(x-2)=(x-5)/(x-2)(x-3) x/2x^2-11x-21=(x+7)/x^2-1 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), (3-x)/(1-x)-(5-x)/(7-x)+(x^2-x)/(x^2-8x+7)=1 解方程(x-2)/(x-3)-(x-3)/(x-4)=(x-5)/(x-6)-(x-6)/(x-7)