The given expression is
(3x + 2)(2x - 7)
A trinomial is a polynomal equation with 3 terms. We would turn the given expression into a trinomial by multiplying each term in the first bracket by each term in the second bracket and adding or subtracting where necessary. It becomes
3x * 2x + 3x * - 7 + 2 * 2x + 2 * - 7
6x^2 - 21x + 4x - 14
6x^2 - 17x - 14
The trinomial is 6x^2 - 17x - 14