##### A

- absolute value
n, the distance on the number line from a number to \(0\text{.}\) For example, the absolute value of \(-7\) is \(7\text{.}\) This fact is expressed by the equation \(\abs{-7} = 7\text{.}\)

- absolute value equation
n, an equation in which the variable occurs between the absolute value bars.

- absolute value inequality
n, an inequality in which the variable occurs between the absolute value bars.

- algebraic expression
n, a meaningful combination of numbers, variables, and operation symbols. Also called an expression.

- algebraic fraction
n, a fraction whose numerator and denominator are polynomials. Also called a rational expression.

- algebraic solution
n, a method for solving equations (or inequalities) by manipulating the equations (or inequalities). Compare with graphical solution and numerical solution.

- allometric equation
n, an equation showing the (approximate) relationship between a living organism's body mass and another of the organism's properties or processes, usually given in the form \(y = k (\text{mass})^p\text{.}\)

- altitude
n, (i) the distance above the ground or above sea level; (ii) the vertical distance between the base and the opposite vertex of a triangle, pyramid, or cone; (iii) the distance between parallel sides of a parallelogram, trapezoid, or rectangle. Also called height.

- amortization
n, the payment of a debt through regular installments over a period of time.

- amount
(in an interest-bearing account), n, the sum of the principal that was invested and all the interest earned.

- amplitude
n, the vertical distance between the midline and the maximum value of a sinusoidal function.

- annuity
n, sequence of equal payments or deposits made at equal time intervals.

- approximation
n, an inexact result.

- area
n, a measure of the two-dimensional space enclosed by a polygon or curve, typically expressed in terms of square units, such as square meters or square feet, etc.

- ascending powers
n, an ordering of the terms of a polynomial so that the exponents on the variable are increasing, such as in the polynomial \(1 + x + x^2\text{.}\)

- associative law of addition
n, the property that when adding three or more terms, the grouping of terms does not affect the sum. We express this formally by saying that if \(a\text{,}\) \(b\text{,}\) and \(c\) are any numbers, then \((a + b) + c = a + (b + c)\text{.}\)

- associative law of multiplication
n, the property that when multiplying three or more factors, the grouping of factors does not affect the product. We express this formally by saying that if \(a\text{,}\) \(b\text{,}\) and \(c\) are any numbers, then \((a \cdot b) \cdot c = a \cdot (b \cdot c)\text{.}\)

- asymptote
n, a reference line (or curve) towards which the graph of an equation tends as the value of x and/or y grows or diminishes without bound.

- augmented matrix (for a linear system with \(n\) variables in standard form),
n, the matrix obtained by making each row of the matrix correspond to an equation of the system, with the coefficients of the variables filling the first \(n\) columns, and the last (that is, the \(n + 1\)) column having the constants.

- axis
n, (plural axes), a line used as a reference for position and/or orientation.

- axis of symmetry
n, a line that cuts a plane figure into two parts, each a mirror image of the other.