A
variable is a symbol used to represent an unknown quantity. Often, variables represent fixed but unknown . Variables are usually denoted with letters such as
x.
x+1=8
In this case,
x is a variable in an . Solving this equation for
x will identify the value of
x that makes the equation true.
x+1=8⇔x=7
Alternatively, a variable can be used to represent a quantity that changes.
Izabella’s income varies depending on thenumber of hours she works. She receives afixed salary of $100 per week plus $4 per hour.
In this case, Izabella's weekly income could be different every week, depending on the number of hours she works. Therefore, the use of a variable is appropriate. Let
x be the hours that Izabella works in a week. Her income can be written by adding the fixed
$100 to the
$4 per hour.
Izabella’s Weekly Income4x+100