## Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

A variable is a symbol that could represent any number. Ex.: $x$ A variable expression contains a variable with constant that will always affect it. Ex.: $3x+5$ An equation has two expressions on opposite sides of an equal sign, which says that the two expressions will also be equal to each other. Example: $3x+5=x-3$
Variable: $x$ can equal anything, from 4, to 9, to 99, or even an expression, such as $2x-2$. Variable expression: An expression is a combination of variables (i.e. $x$, $y$) and constants (i.e. 3,5). Equation: An equation is stating that two expressions are equal, such as $9x$ being equal to 10 making $9x=10$.