A good way to approach this is using the FOIL method.
Multiply first two (F):
\(2x * 3x = 6x^2\)
Then outer two (O):
\(2x * 4 = 8x\)
Then inner two (I):
\(3 * 3x = 9x\)
Then last two (L):
\(3 * 4 = 12\)
Add them up:
\(6x^2 + 8x + 9x + 12\)
\(6x^2 + 17x + 12\)
Hope this helps :)
