Помогитеее!!!!!!!!!!!!!

1)
$\frac{{a}^{2} + 6ab + 9 {b}^{2}}{a + 3b } = \frac{(a + 3b)(a + 3b)}{a + 3b} = a + 3b$
2)
$\frac{25 {b}^{2} - 40bc + 16 {c}^{2} }{15b - 12c} = \frac{(5b - 4c)(5b - 4c) }{3(5b - 4c)} = \frac{5b - 4c}{3}$
3)
$\frac{2x - 3y}{4 {x}^{2} - 12xy + 9 {y}^{2} } = \frac{2x - 3y}{(2x - 3y)(2x - 3y)} = \frac{1}{2x - 3y}$
4)
$\frac{36 {x}^{2} + 84xy + 49 {y}^{2} }{24x + 28y} = \frac{(6x + 7y)(6x + 7y)}{4(6x + 7y)} = \frac{6x + 7y}{4}$