Please help me with this algebra question:?

a=-2 or a=-7/3

Since 6^2 is 36, factors with 6a in each are a good starting point:

(6a +- ?)(6a +- ?)

Since the 1 in the trinomial is positive, the signs in the factors are the same. Since the 12a is positive, both are plus signs.

(6a + ?)(6a + ?)

The only factors of 1 are 1 and 1. Since 1 times 6a plus 1 times 6a gives you the desired 12a, you're done.

(6a + 1)(6a + 1) or (6a + 1)^2

If the a term in the original trinomial had a different coefficient, you would have needed to factor the 36a^2 term differently so that adding one times each factor would sum to the desired value. For example, if the a term had a coefficient of 37, the factors would need to be 36a and a. If the coefficient were 20, the factors would need to be 18a and 2a. Each gives a product of 36a^2 but adds to a different coefficient on the a term.