Answer:
x^2 + 14x + 49
Explanation:
The current expression is a binomial because it has two terms (x and a 7).
To make it a trinomial, we multiply x + 7 by itself (because it is getting squared in the expression).
(x + 7)^2 can be written as (x + 7)(x + 7).
To simplify that out, we use the method FOIL. Foil essentially means you multiply the FIRST two values in the parenthesis, and then the OUTSIDE values of the parenthesis and then the INSIDE values of the parenthesis, finally multiplying the LAST values in the parenthesis. This is how it looks:
(x * x) + (7 * x) + (7 * x) + (7 * 7).
Simplifying, we get x^2 + 14x + 49, which has three terms, thus making it a trinomial.
Hope this helps! :)