A term is defined as a part of an equation separated by a +/- operation. Because there is a + operation separating two terms (-x^6 and 7x^5), the expression is a binomial, meaning the expression has two terms.
The highest exponent or degree, present in the expression is to the power of 6. Therefore, the expression is in the sixth degree.
Taken together, the expression is a sixth-degree binomial.