What is a special kind of expression where each term is a constant, variable or a product of constants and variables.

Consider the expression  . We want to combine the two terms and write the expression in the form  , where   and   are constants, and  .

Terms can be added or subtracted to form an expression.

A single variable, a constant, a combination of these as a product or quotient forms a

Expression is a combination of ___________, ____________ and _______________Select one or more:a.functionsb.variablesc.constantsd.operatorse.keywords

Which of the following describes a variable? A. the part of an expression that includes parentheses B. a letter or symbol that represents a value that never changes C. a letter or symbol that represents an unknown quantity D. the part of an expression that always remains the same