Answer:
um idk but thanks for the points
18%=0.18
380×0.18=68.4 increase
380+68.4=448.4
the easier way is to think 1 times any number is the same number so 380(1+0.18)=448.4 (just like adding tax to the price of something to see how much you'll actually pay)
When you make the product of a binomial of the kind x + a times other binomial that is of the kind x - a, you obtain another binomial (not a trinomial), so any example with that form will be a counterexample that disproves the conjecture:
(x + a) * (x - a) = x^2 - a^2
For example, (x +3) * (x - 3) = x^2 - 9. So, not always the product of two binomials is a trinomial.