Which expressions are polynomials?

select each correct answer.
1)6 + p

2)x – 1

3)8x−z3

4)5x2−x√

i believe that the slope of the line is -5

step-by-step explanation:

1^3 + 2^3 + 3^3 +4^3 = (1+2+3+4)^2

step-by-step explanation:

i am only able to answer the first part. i am not sure about the second part. sorry