First let's multiply the first and last term together:

(3x + 4)(3x – 4) = 9x^{2} – 16

Then we can multiply the two binomials (9x^{2} – 16) and (5x + 6).

If instead we first multiplied (3x + 4) and (5x + 6), we would need to multiply (15x^{2} + 38x + 24) by (3x – 4), which would be an ugly calculation. Don't do that to yourself. You're a good person and deserve better.

Whichever way we do it, though, we should find the same final answer: