Question

номер 173 сборник 8 класс!

Answer 1

Ответ:

$\displaystyle 1)\ \ \frac{a^2-1}{a^2-1}=\frac{(a-1)(a+1)}{(a-2)(a+2)}\\\\\\a=1:\ \frac{(1-1)(1+1)}{(1-2)(1+2)}=0\\\\a=5:\ \frac{4\cdot 6}{3\cdot 7}=\frac{24}{21}\\\\a=-5:\ \frac{-6\cdot (-4)}{-7\cdot (-3)}=\frac{24}{21}\\\\a=6:\ \frac{5\cdot 7}{4\cdot 8}=\frac{35}{32}$

$\displaystyle 2)\ \ \frac{4-t^2}{16-t^2}=\frac{4-t^2}{(4-t^2)(4+t^2)}=\frac{1}{4+t^2}\\\\\\t=-1:\ \frac{1}{4+1}=\frac{1}{5}\\\\t=2:\ \frac{1}{4+4}=\frac{1}{8}\\\\t=-2:\ \frac{1}{4+4}=\frac{1}{8}\\\\t=3:\ \frac{1}{4+9}=\frac{1}{13}$