A quadratic equation is one of the standard forms for equations in algebra, a quadratic equation in standard form looks like this:
ax2 + bx + c = 0
the name for quadratic equations comes from quad, meaning squared as the variable is squared. Sometimes elements of quadratic equations are not shown, for example, if a = 1 it is not shown and if c = 0 it is not shown either.
sometimes quadratic equations can be disquised and not look like they do in standard form, for example x2 = 3x - 1 in standard form it look like this, x2 - 3x + 1 = 0, when you have a hidden quadratic equation like this, you have to move all the terms to left hand side, and remember that postives become negatives and vice versa when moved the another side of the equals.