Solve

$\displaystyle 27^{x} (9^{2x - 1}) = 3^{x + 4}$

My work:

$\displaystyle 3^{3x} (3^{4x-2}) = 3^{x+4}$

$\displaystyle (3x)(4x-2) = x+4$

$\displaystyle 12x^2 - 6x - x - 4 = 0$

$\displaystyle 12x^2 - 7x - 4 = 0$

Now I'm stuck, I can't find any factors that has the product of 48 and the sum of -7.

Textbook Answer: 1