# quadratic

A quadratic is an expression or an equation that contains the variable squared, but not
raised to any higher power. For instance a **quadratic equation** in *x* contains *x*^{2} but not *x*^{3}.
Similarly a **quadratic expression**, or a **quadratic
form**, contains its variable(s) squared but not raised to any higher
power. If there is more than one variable (say, *x* and *y*),
quadratic can mean that they are multiplied together in pairs (*xy*)
but not in threes (such as *x*^{2}*y*). The graph of a
quadratic equation is known as a **quadratic curve**; the curve
of the general quadratic equation *y* = *ax*^{2} + *bx* + *c* is a parabola.