please help me :'(

Polynomial Function.
Tell whether the following is a polynomial is a polynomial function or not. give the degree and the number of terms for polynomial functions.
1. y = 3x² - 2x + 4
2. y = 5^x+3
3. y = x + 4/3
4. y = (x - 4)(4x + 1)
5. y = 6x² + 1​