ACT Algebra & Arithmetic

Slope formula

(y₂ - y₁)/(x₂ - x₁)

Slope-intercept form

y = mx + b (m = slope

Point-slope form

y - y₁ = m(x - x₁)

Standard form of a linear equation

Ax + By = C

Vertex form of a quadratic

y = a(x - h)² + k

Quadratic formula

x = [-b ± √(b² - 4ac)] / (2a)

Factoring trinomials

ax² + bx + c = (mx + n)(px + q)

Difference of squares

a² - b² = (a - b)(a + b)

Completing the square

Rewrite ax² + bx + c as a(x - h)² + k

Zero product property

If ab = 0

Absolute value definition

|x| = x if x ≥ 0

Average (mean)

Sum of terms ÷ Number of terms

Median

Middle value in an ordered list

Mode

Most frequent value

Percent change

[(New - Original)/Original] × 100

Compound interest formula

A = P(1 + r/n)^(nt)

Simple interest formula

I = Prt