Variable: A letter that stands for a number
Constant: A fixed number that does not change
Coefficient: The number multiplying a variable
Term: A part of an expression separated by + or −
Like terms: Terms with the same variables raised to the same powers
Expression: A combination of numbers, variables and operations without an equals sign
Equation: A statement that two expressions are equal
Inequality: A statement comparing two expressions using <, >, ≤ or ≥
Solve: Find the value of the variable that makes the statement true
Evaluate: Replace variables with numbers and compute the result
Simplify: Combine like terms and reduce an expression
Factor: Write an expression as a product of simpler expressions
Expand: Multiply out brackets to remove them
Substitution: Replacing a variable with a value or another expression
Linear equation: An equation whose graph is a straight line; the variable has degree 1
Slope-intercept form: y = mx + b
Point-slope form: y − y₁ = m(x − x₁)
Standard form of a line: Ax + By = C
Slope: Rise over run; change in y divided by change in x
Rise: The vertical change between two points
Run: The horizontal change between two points
Y-intercept: Where a graph crosses the y-axis (x = 0)
X-intercept: Where a graph crosses the x-axis (y = 0)
Parallel lines (slopes): Have equal slopes
Perpendicular lines (slopes): Slopes are negative reciprocals; their product is −1
Slope of a horizontal line: 0
Slope of a vertical line: Undefined
Function: A rule that gives each input exactly one output
Function notation: f(x) is read 'f of x'; the output for input x
Domain: All allowed input values
Range: All resulting output values
Independent variable: The input variable, usually x
Dependent variable: The output variable, usually y; it depends on x
Vertical line test: A graph is a function if no vertical line crosses it twice
Absolute value: The distance of a number from zero, written |x|
System of equations: Two or more equations solved together
Substitution method: Solve one equation for a variable and substitute into the other
Elimination method: Add or subtract equations to cancel a variable
Consistent system: A system with at least one solution
Inconsistent system: A system with no solution, such as parallel lines
Dependent system: A system with infinitely many solutions; the same line
Polynomial: An expression of terms with whole-number powers of variables
Degree: The highest power of the variable in a polynomial
Standard form of a polynomial: Terms written from the highest power to the lowest
Quadratic equation: An equation of the form ax² + bx + c = 0
Quadratic formula: x = (−b ± √(b² − 4ac)) / 2a
Completing the square: Rewriting a quadratic so a perfect square trinomial appears
Vertex form: y = a(x − h)² + k
Difference of squares: a² − b² = (a − b)(a + b)
Perfect square trinomial: a² + 2ab + b² = (a + b)²
Greatest common factor (GCF): The largest factor shared by all the terms
Zero product property: If ab = 0, then a = 0 or b = 0
Root, zero or solution: An x value where the function equals 0
Radical: A root symbol, such as √
Rationalize the denominator: Rewrite a fraction so the denominator has no radical
Rational expression: A fraction whose numerator and denominator are polynomials
Inverse variation: y = k/x; as one quantity goes up, the other goes down
Direct variation: y = kx; the ratio y/x is constant
Constant of variation: The constant k in a variation equation
Arithmetic sequence formula: aₙ = a₁ + (n − 1)d
Geometric sequence formula: aₙ = a₁ · rⁿ⁻¹
Exponential growth: y = a(1 + r)^t with r > 0
Exponential decay: y = a(1 − r)^t with 0 < r < 1
Compound interest formula: A = P(1 + r/n)^(nt)
Continuous compounding formula: A = Pe^(rt)

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