Algebra I Recipe: Variables in Algebra

1. variable – any letter representing a number.
2. algebraic expression – an expression having numbers and variables with operations,
   such as 2x - y.

1. Substitute the given value in for each variable.
2. Perform the operations the same as evaluating numerical expressions in Sec. 1.1.

1. Interest Earned I = Prt
• Interest = Principal · rate · time
• Rate – must be in decimal form
• Time – must be in years such as 6 months = 0.5 years
2. Temperature ºF = (9/5)ºC + 32
• ºF is degrees Fahrenheit
• ºC is degrees Celsius
3. Distance d = rt
• distance = rate · time
• time – must be in hours such as 15 minutes = 0.25 hours

Practice Problems