First, we can factory both sides of this division problem by using important rules.
First, (9x^2 - 1) can be simplified using difference of squares, which states:
(a^2 - b^2) = (a + b)(a - b)
In this case, the numerator can be simplified to (3x + 1)(3x - 1)
Now, we can also simplify the denominator using the AC method.
By splitting the middle term to factors of 12, we can factor this trinomial has a pair of binomials.
12x^2 + 4x + 3x + 1
Factor binomials.
4x(3x + 1) + 1(3x + 1)
Rearrange.
(4x + 1)(3x + 1)
Let's bring our binomial groups together.
(3x + 1)(3x - 1)/(4x + 1)(3x + 1)
We have the same factor, (3x + 1), in both the numerator and the denominator.
Because of this, we can cancel both factors out, which leaves:
(3x - 1) / (4x + 1), which is the solution.