An equation includes only second degree polynomials.
Some examples are y = 3x2 – 5x2 +
1, x2 + 5xy + y2 =
1, and 1.6a2 +5.9a – 3.14
Note: When there is only one variable, a quadratic equation can
be expressed in
the form ax2 + bx + c =
0 where a, b,
and c are all constants.