What are the leading coefficient, constant term and degree, if any, of the algebraic expression -7?

Pls me this is due today and i need i will make brainliest if you me answer correctly and i will report if you try to give me a dumb answer.

What is the length of the unknown leg in the right triangle ?

What set does not contain -3 the set of all real numbers the set of all integers the set of all whole numbers the set of all rational numbers