Сократите:
1) $\frac{(3a + 3b)^2}{a + b}$;
2) $\frac{(6x - 18y)^2}{x^2 - 9y^2}$;
3) $\frac{xy + x - 5y - 5}{4y + 4}$;
4) $\frac{a^2 - ab + 2b - 2a}{a^2 - 4a + 4}$.
$\frac{(3a + 3b)^2}{a + b} = \frac{9(a + b)^2}{a + b} = 9(a + b)$
$\frac{(6x - 18y)^2}{x^2 - 9y^2} = \frac{36(x - 3y)^2}{(x - 3y)(x + 3y)} = \frac{36(x - 3y)}{x + 3y}$
$\frac{xy + x - 5y - 5}{4y + 4} = \frac{(xy + x) - (5y + 5)}{4(y + 1)} = \frac{(x(y + 1) - 5(y + 1)}{4(y + 1)} = \frac{(y + 1)(x - 5)}{4(y + 1)} = \frac{x - 5}{4}$
$\frac{a^2 - ab + 2b - 2a}{a^2 - 4a + 4} = \frac{(a^2 - ab) + (2b - 2a)}{(a - 2)^2} = \frac{a(a - b) + 2(b - a)}{(a - 2)^2} = \frac{a(a - b) - 2(a - b)}{(a - 2)^2} = \frac{(a - b)(a - 2)}{(a - 2)^2} = \frac{a - b}{a - 2}$
Пожауйста, оцените решение
