Question

пплиииззззз дам 30 бал ​

Answer 1

$\displaystyle\bf\\\frac{2a^{2} +4}{a^{2} -1} -\frac{a-2}{a+1} -\frac{a+1}{a-1} =\frac{2a^{2} +4}{(a-1)\cdot(a+1)} -\frac{a-2}{a+1} -\frac{a+1}{a-1} =\\\\\\=\frac{2a^{2} +4-(a-2)\cdot(a-1)-(a+1)\cdot(a+1)}{(a -1)\cdot(a+1)} =\\\\\\=\frac{2a^{2} +4-(a^{2} -a-2a+2)-(a^{2} +2a+1)}{(a -1)\cdot(a+1)} =\\\\\\=\frac{2a^{2} +4-a^{2} +3a-2-a^{2} -2a-1}{(a -1)\cdot(a+1)} =\\\\\\=\frac{a+1}{(a -1)\cdot(a+1)} =\frac{1}{a-1} \\\\\\\frac{1}{a-1} =\frac{1}{a-1}$

Тождество доказано