Please help! stuck on this test and can’t figure any questions out.

What are “like terms”? why can we only add like terms?

Interpret the following expression (5y^2-7)^3/(2y)^2

Which graph correctly represents the equation  y=−4x−3? guys me iam not trying to fail summer school and will offer 40 points for who ever me with the next 3 problems and will give brainlest