Answer by
mamapuppy (241)

You use FOIL to multiply the two factors, which means multiply the First, Outer, Inner, then Last parts of each factor together. First - 9x*3x=27x2 (the 2 means squared)
Outer - 9x*2=18x
Inner - -4*3x=-12x
Last - -4*2=-8
Then combine to get 27x2+6x-8