a plus sign, the other with a minus sign. For example, y = x ± 1 represents the two equations y = x + 1 and y = x − 1. Sometimes, it is used for denoting a positive-or-negative term such as ±x. Arithmetic vs algebraic operations Algebraic operations work in the same way as arithmetic operations, as can be seen in the table below. Note: the use of the letters and is arbitrary, and the examples would have been equally valid if and were used. Properties of arithmetic and algebraic operations See also Algebraic expression Algebraic function Elementary algebra Factoring a quadratic expression Order of operations Notes References Elementary algebra Elementary mathematics