Algebra 1 UNIT 2 Formulas and Functions OBJECTIVES: Solve formulas for different variables. Solve equations for y so that y is a function of x.

Vocabulary Formula - an algebraic equation that relates 2 or more real life quantities Example: V = lwh (volume of a rectangle) Non-Example: 2x + y = 3 Function Form – An equation solved for y so that y is a function of x. Example: y = -7x + 3 Non-example: -4x + 2y = 5

#1 Distance Formula Solve for r in d = rt d = rt Rewrite original formula t t Isolate r by dividing both sides by t Example problem: If you ride your bike for 2.5 hours and travel 37.5 miles, what is your average speed?

#2 Interest Formula Solve I = prt for r. I = prt Rewrite the original formula pt pt Isolate r by dividing by pt Example problem: Find the rate when $2800 was invested for 4 years and earned $504 Interest.

#3 Area of a Prism Formula S - Ph = B Solve for B. S = 2B + Ph S = 2B + Ph Write original formula -Ph - Ph Subtract Ph from each side S - Ph = 2B _____________ ______ 2 2 Isolate B by dividing both sides by 2 S - Ph = B 2

Practice Problems 1) 2)

Rewriting an Equation in Function Form #4 Rewriting an Equation in Function Form Rewrite the equation so y is a function of x. 6y - 12x = 18 6y - 12x = 18 Rewrite the original equation +12x +12x Add 12x to both sides 6y = 12x + 18 ______ ________ ________ 6 6 6 Divide both sides by 6 y = 2 x + 3

Rewriting an Equation in Function Form #5 Rewriting an Equation in Function Form Rewrite the equation so y is a function of x. -3y + 2x = 15 -3y + 2x = 15 Rewrite the original equation -2x -2x Subtract 2x to both sides -3y = -2x + 15 ______ _______ _______ -3 -3 -3 Divide both sides by -3

Practice Problems 1) 2)