Study
Formula and reference sheets
Original Marlow Works notes—not an official formula packet.
Slope of a line
m = (y₂ − y₁) / (x₂ − x₁)
Change in y divided by change in x between two points.
Percent change
percent change = (new − original) / original
A 20% increase multiplies by 1.20; a 20% decrease multiplies by 0.80.
Quadratic formula
x = (−b ± √(b² − 4ac)) / (2a)
Solves ax² + bx + c = 0 when factoring is inconvenient.