Quadratic Equation is an equation which contains an `x^2` term (or if you want to get technical it is an equation containing a single variable of degree2 with no higher power).
A quad bike with a rat (quadratic) driving, pulling an X-ray (X) of a fish in a square (2) fish tank.
A quadratic equation is an equation which contains a `x^2` term.
All of the equations contain a `x^2` term therefore they are called quadratic equations.
This is a well known quadratic equation i.e. containing `x^2`
These are NOT quadratics because the first has another variable with degree squared and the second has one with a higher power than 2.