7x=x^2-8,x=?

x+2x+3x+4x+5x+6x+7x+8x+9x=9x-8x-7x-6x-5x-4x-3x-2x-x.x等于多少? (x+12)(x-2)+(x+7)(x+8)-(x+5)(x-10),其中x=2 X-5+8*X=7*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 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1+x+x^2+x^3=0,求x+x^2+x^3+x^4+x^+x^6+x^7+x^8的值 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 x+2/x+3－x+1/x+2=x+8/x+9－x+7/x+8 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) 解方程:(x+3)/(x+2)-(x+5)/(x+4)=(x+7)/(x+6)-(x+9)/(x+8)