Chapter 1

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Chapter 1 Tools of Algebra

• 1.5 Rewriting Equations and Formulas

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1.5 Rewriting Equations and Formulas

• In this section we will review
• Rewriting common formulas and equations that have
  more than one variable

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1.5 Rewriting Equations and Formulas

• When an equation has more than one variable, you
  can solve for ANY of the variables.

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1.5 Rewriting Equations and Formulas

• Common formulas
• Distance
• d rt
• d distance, r rate, t time
• Simple Interest
• I Prt
• I interest, P principle, r rate, t time

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1.5 Rewriting Equations and Formulas

• Common formulas
• Temperature
• F 9/5 C 32
• F degrees Fahrenheit, C degrees Celsius

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1.5 Rewriting Equations and Formulas

• Geometry Formulas
• Rectangle
• Perimeter
• P 2l 2w
• Area
• A lw
• Triangle
• Perimeter
• P a b c
• Area
• A ½ bh

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1.5 Rewriting Equations and Formulas

• Geometry Formulas
• Trapezoid
• Area
• A ½ (b1 b2)h
• Circle
• Circumference
• C pd or C 2pr
• Area
• A pr2

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1.5 Rewriting Equations and Formulas

• Example 1
• Solve the formula F ma for a.

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1.5 Rewriting Equations and Formulas

• Example 2
• Solve the formula PE mgh for h.

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1.5 Rewriting Equations and Formulas

• Example 3
• A conservationist wants to survey a circular lake
  but cannot measure the diameter of the lake
  directly. Instead, the conservationist measures
  the circumference. It is 2 1/3 miles. What is
  the diameter of the lake, to the nearest ¼ mile?

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1.5 Rewriting Equations and Formulas

• Example 4
• Find the value of y in the equation 3x 4y
  10 when x -2 and when x 6.

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1.5 Rewriting Equations and Formulas

• Example 5
• A campus bookstore sells T-shirts for 15 each
  and sweatshirts for 22 each. Write an equation
  with more than one variable for the bookstores
  revenue R from selling m T-shirts and n
  sweatshirts.

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1.5 Rewriting Equations and Formulas

• Example 6
• If the campus bookstore needs to have 6600 in
  revenue from sales of these two items. What are
  some combinations of T-shirts and sweatshirts
  that will meet this objective?

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1.5 Rewriting Equations and Formulas

• HOMEWORK
• Worksheet 1.5
• 1 3, 13 25 all