What is a polynomial equation of degree two?

It is also known as a 'Quadratic Eq'n'.

It is algebraically expressed as

Ax^(2) + Bx + C = 0

The 'A' 'B' & 'C' can be any number.

The 'degree 2' comes the maximum power/exponential of 'x' , which is 'x' raised to the second power ' x^(2)'.