believe what you're asking is to turn the trinomial into two binomials
So you first have to get 3x²; the only way to get this is
(3x )(x ) when multiplying that, you would get 3x²
when dealing with the -8x and the 4, you must find numbers that are factors of four (when multiplied together they will equal 4) and will multiply with the x's to get -8
(3x-2)(x-2)
you can tell that this is the answer because when you multiply though you will get:
3x-2x²-6x+4
or: 3x²-8x_4
Hope this helped