Download Chapter 3 – Solving Linear Equations

Chapter 3 – Solving
Linear Equations
3.7 – Formulas and Functions
3.7 – Formulas and Functions
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Today we will learn how to:
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Solve a formula for one of its variables
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Rewrite an equation in function form
3.7 – Formulas and Functions
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So far, we have been working with
equations that have one variable.
Today, we are going to work with
equations that have more than one
variable.
3.7 – Formulas and Functions

Formula – an algebraic equation that
relates two or more real-life quantities
3.7 – Formulas and Functions
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Example 1


Solve A = lw for w.
Find the width of a rectangle that has an area
of 42 ft.2 and a length of 6 ft.
3.7 – Formulas and Functions
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Example 2
5
 Solve K  F  32   273 for F.
9
3.7 – Formulas and Functions
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Example 3

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Solve I = Prt for t.
Find the number of years t that $2800 was
invested to earn $504 at 4.5%
3.7 – Formulas and Functions
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When you have an equation with x and y,
you can re-write the equation two ways.
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“y is a function of x” means you rearrange the
equation so you have y =
“x is a function of y” means you rearrange the
equation so you have x =
3.7 – Formulas and Functions

Example 4

Rewrite the equation 2x – y = 9 so that y is a
function of x.
3.7 – Formulas and Functions
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Example 5
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Write the equation 2x – y = 9 so that x is a
function of y.
Use the result to find x when y = -2, -1, 0,
and 1.
3.7 – Formulas and Functions
HOMEWORK
Page 177
#11 – 14, 16 – 34 even