Question

Выполните действия :
a) 4/a + (a-4)/(a+3) = b) (2x^2)/(x^2-4) - 2x/(x+2) =
ответе пж даю 100 баллов

Answer 1

Ответ:

а

$\frac{4}{a} + \frac{a - 4}{a + 3} = \frac{4(a + 3) + a(a - 4)}{a(a + 3)} = \\ = \frac{4a + 12 + a {}^{2} - 4a}{a(a + 3)} = \frac{ {a}^{2} + 12}{a(a + 3)}$

б

$\frac{2 {x}^{2} }{ {x}^{2} - 4 } - \frac{2x}{x + 2} = \frac{2 {x}^{2} }{(x - 2)(x + 2)} - \frac{2x}{x + 2} = \\ = \frac{2 {x}^{2} - 2x(x - 2)}{(x - 2)(x + 2)} = \frac{2 {x}^{2} - 2 {x}^{2} + 4x}{(x - 2)(x + 2)} = \\ = \frac{4x}{ {x}^{2} - 4}$