Question

Помогите решить пример плиз

Answer 1

$\frac{(3 {a}^{2} - 7a)(3a + 7) }{49 - 9 {a}^{2} } = \frac{a(3a - 7)(3a + 7)}{49 - 9 {a}^{2} } = \frac{a(9 {a}^{2} - 49)}{49 - 9 {a}^{2} } = \frac{ -a(49 - 9 {a}^{2})}{49 - 9 {a}^{2} } = - a$