Question

A parabola opens down if the value of (a b or c) is negative in the general form of the equation.

Answer 1

y = ax² + bx + c
(opens up if a > 0 and down if a < 0)

Answer 2

some people compare it to a happy/sad face if that makes it easier to remember (positive a = graph that looks like a U or a smiley face. negative a = graph that opens down or a sad face)

Answer 3

thanks!