Answer:
7x^4+x^3 (or 7x^4 + some random term)
Explanation:
Since the polynomial expression must be a binomial, it must have two terms.
Since the binomial must have a degree of 4, and the leading coefficient must be 7, then a possible binomail could be 7x^4+x^3 because you have two terms, 7x^4 and x^3 while the degree is 4 and the leading coefficient is 7.