Question

Упростите выражение

Answer 1

$\frac{4 - a}{a} + \frac{a}{4 + a} = \frac{(4 - a)(4 + a) + {a}^{2} }{a(a + 4)} = \\ = \frac{16 - {a}^{2} + {a}^{2} }{a(a + 4)} = \frac{16}{ {a}^{2} + 4a }$
$\frac{2 - c}{2 + c} - \frac{2 + c}{2 - c} = \\ \frac{(2 - c) {}^{2} { - (2 + c) {}^{2} }^{} }{4 - {c}^{2} } = \frac{4 - 4c + {c }^{2} - 4 - 4c - {c}^{2} }{4 - {c}^{2} } = 0$