Question

What's the quadratic equation?

Answer 1

The standard form of the quadratic equation is ax^2 + bx + c. In vertex form, it's y = a(x – h)2 + k. 
The graph of a quadratic equation is a parabola, which looks like a u. If a is negative then it's an upside down u.

Answer 2

in 8th grade my algebra teacher made us memorize the quadratic equation song (to the rhythm of pop goes the weasel):

x equals negative b plus or minus the square root of b squared minus 4ac all over 2a