Formulas and Applications

Kamal Hennayake

Introduction A formula is an equation that uses

letters to express relationship between two or more variables.

A mathematical model is a formula or algebraic equation that can be formed from a verbal model or from actual data.

Example Write the phrase “the quotient of

12 and a number, decreased by 3 times the number” as an algebraic expression.

Solution: Let x be the number.The quotient of 12 and a number: 12

x

Example 1 Write the phrase “the quotient of

12 and a number, decreased by 3 times the number” as an algebraic expression.

Solution: Let x be the number.The quotient of 12 and a number

decreased by 3 times the number: 12

3x

x

Steps for Setting up Applied Problems Read the problem carefully, perhaps

two or three times. (What are we looking for?).

Assign a letter (variable) to represent what we are looking for.

Make a list of all the known facts, and translate them into mathematical expressions or an equation.

Solve the equation for the variable and then answer the given question.