Сократите дробь 9х2 - 6х + 1 /6х2 + х - 1 Подробно?Спасибо!

Решите задачу:

$\displaystyle \frac{9x^{2}-6x+1}{6x^{2}+x-1}= \frac{9(x-1/3)^{2}}{6(x-1/3)(x+1/2)}=\frac{3(x-1/3)}{2(x+1/2)}= \frac{3x-1}{2x+1} \\ \\ \\ 9x^{2}-6x+1=0 \\ D=b^{2}-4ac=36-36=0 \\ x_{1,2}=1/3 \\ 9x^{2}-6x+1=9(x-1/3)^{2}\\ \\ 6x^{2}+x-1=0 \\ D=b^{2}-4ac=1+24=25 \\ x_{1}=1/3 \\ x_{2}=-1/2 \\ 6x^{2}+x-1=6(x-1/3)(x+1/2)$