Question

$\frac{a}{a - 6} - \frac{3}{a + 6} + \frac{ {a}^{2} }{36 - {a}^{2} }$
Помогите решить!

Answer 1

$\frac{a}{a - 6} - \frac{3}{a + 6} + \frac{ {a}^{2} }{36 - {a}^{2} } = \frac{a(a + 6) - 3(a - 6) - {a}^{2} }{(a - 6)(a + 6)} = \\ = \frac{ {a}^{2} + 6a - 3a + 18 - {a}^{2} }{(a - 6)(a + 6)} = \frac{ 3a + 18 }{(a - 6)(a + 6)} = \frac{3(a + 6)}{(a + 6)(a - 6)} = \\ = \frac{3}{a - 6}$