Question

解方程(3x^2+9x+7)/(x+1)-(2x^2+4x-3)/(x-1)-(x^3+x+1)/(x^2-1)=0

Answer 1

方程两边同时乘以x²-1:

(3x²+9x+7)(x-1)-(2x²+4x-3)(x+1)-(x³+x+1)=0

3x^3+9x^2+7x-3x^2-9x-7-(2x^3+4x^2-3X+2x^2+4x-3)-x^3-x-1=0

3x^3+6x^2-2x-7-2x^3-4x^2+3x-2x^2-4x+3-x^3-x-1=0

0*x^3+0*x^2-4x-7-1+3=0

-4x-5=0

-4x=5x

x=-5/4

经检验x=-5/4为原方程的解.

望采纳!谢谢!