Extra formulae

Question 1

What is the quadratic formula

Answer 1

x = -b±√b²-4ac / 2a

Question 2

Compound interest

Answer 2

(amount x decimal multiplier)^n (n = number of years)

P (1 + r/100)^n (P = initial amount, r = interest rate over given period, n = number of periods)

Question 3

What are the rules when trying to find the nth term of a quadratic sequence?
an² + bn + c

Answer 3

2a = second difference (always constant)
3a + b = second term - first term
a + b + c = first term