how do u factor

25a^2 - 30a + 9

If there are any rational roots, the numerator will divide 9, and the denominator will divide 25.

That means that the factors will be somewhere in

(25a-1)(a-9)
(25a-3)(a-3)
(25a-9)(a-1)

(5a-1)(5a-9)
(5a-3)(5a-3) <-----
(5a-9)(5a-1)

Review your FOIL rules if it's not clear why this is the correct factorization.