Question 598781
Quadratic is what we call polynomials expressions, or functions of degree 2, like
{{{x^2+5x-3}}} or {{{f(x)=x^2-64}}} or {{{y=x^2}}} or {{{(1/2)k^2-2k+1}}}.
All those expressions have a variable squared. It may be multiplied by a number and there may be other terms added.
We call functions like {{{f(x)=x^2-64}}} or {{{y=x^2}}} quadratic functions.
We call the expressions like {{{x^2+5x-3}}} , {{{x^2-64}}} , {{{x^2}}} , {{{(1/2)k^2-2k+1}}} quadratic polynomials.
When one of those expressions is set as equal to zero, we have a quadratic equation, like
{{{8x^2+13x-6=0}}}
Sometimes we call that just a quadratic for short.