Сократить дробь:

а) 5 а²+19 а-4 =

1-25 а²

б) х²+х-6=

7 х+21

1) 5a² + 19a - 4 = (5a - 1) (a+4)

= (5a - 1) (a+4) / (1 - 5a) (1+5a) =

= - (1 - 5a) (4+a) / (1 - 5a) (1+5a) =

= - (4+a) / (1+5a)

2) x² + x - 6 = (x+3) (x - 2)

= (x+3) (x - 2) / 7 (x + 3) (x - 2) / 7