density formula
density = mass/volume
speed formula
speed = distance/time
vertex formula
y = a(x - h)² + k
completing the square
c = (b/2)²
zero product property
if ab = 0, either a = 0 or b = 0
trigonometry in different quadrants
product of the roots
c/a
sum of the roots
-b/a
percent change (increase/decrease)
new - old / old
compound interest
A = P(1 + r)^t
compound interest (but its compounded more than once per year)
A = P (1 + r/n)^nt (n is the number of times interest is compounded per year)
simple interest
A = P(1 +rt)
sum of angles in a polygon
180(n-2)
exterior angle
sum of the two angles furthest away from it
finding vertex formula
-b/2a