3'7 Formulas and Functions

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3.7 Formulas and Functions

• Algebra 1 Honors

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Vocabulary

• Formula - an algebraic equation that
• relates 2 or more real life
  quantities
• Function Form -a two-variable equation written so
  that one of its variables is isolated on one side
  of the equation
• Ex) Rewrite 7x - y 3 so that y is a Function
• of x is rewritten as y -7x 3

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Distance Formula

• Solve for r in d rt
• d rt Rewrite original formula

t t Isolate r by dividing both
sides by t
Simplify
If you ride your bike for 2.5 hours and travel
37.5 miles, what is your average speed?
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Interest Formula

• Solve I prt for r.
• I prt Rewrite the original formula

pt pt Isolate r by dividing by pt
I/pt r Simplify

• Find the rate when 2800 was invested for 4 years
  and earned 504 Interest.

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Solving Formulas

• Use the formula for the area of a
• right prism. Solve for B.
• S 2B Ph Write original formula
• -Ph - Ph Subtract Ph from each
  side
• S - Ph 2B Simplify
• ________ ________
• 2 2 Isolate B by dividing both
  sides by 2
• S - Ph B Simplify
• 2

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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 18 12x Simplify
• ______ ______________________
• 6 6 Divide both sides by
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• y 3 2 x Simplify

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