Сделайте !! please номер 10

А) ОДЗ:3x+9≠0
3(x+3)≠0
x+3≠0
x≠-3
$\frac{ {x}^{2} - 9}{3x + 9} = \frac{(x - 3)(x + 3)}{3(x + 3)} = \frac{x - 3}{3}$
б) ОДЗ:2x-4≠0
2(x-2)≠0
x-2≠0
x≠2
$\frac{ {x}^{2} - 4 }{2x - 4} = \frac{(x - 2)(x + 2)}{2(x - 2)} = \frac{x + 2}{2}$
в) ОДЗ:a²-9≠0
(a-3)(a+3)≠0
a-3≠0
a≠3
a+3≠0
a≠-3
$\frac{ {a}^{2} - 6a + 9}{ {a}^{2} - 9} = \frac{ {(a - 3)}^{2} }{(a - 3)(a + 3)} = \frac{a - 3}{a + 3}$
г) ОДЗ:y²-49≠0
(y-7)(y+7)≠0
y-7≠0
y≠7
y+7≠0
y≠-7
$\frac{7y - 49}{ {y}^{2} - 49 } = \frac{7(y - 7)}{(y - 7)(y + 7)} = \frac{7}{y + 7}$