3.7 Formulas & Functions
Objectives
SWBAT:
• Solve a formula for one of its variables
• Rewrite an equation in function form
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Solving Formulas
Formula: an algebraic equation that relates two or more real­life quantities
Ex: Area of a rectangle (A = lw)
Distance (d = rt)
Simple Interest (I = prt)
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Examples
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Example 2
A triangle has an area of 72 ft². Its base is
18 ft. Find the height of the triangle.
Solve for h in the formula: A = ½ b h
A = ½ b h
72 = ½ 18 h 72 = 9 h
h = ?
8 = h
The height of the triangle is 8 ft.
b = 18 ft.
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Rewriting Equations in Function Form
Ex: x + y = 5 (Rewrite this equation so that y is a function of x ­­­>>>) y = … )
x + y = 5 Solve for y
­x ­x (Subtract x from each side)
y = 5 ­ x
Rewrite the equation x + y = 5 so that x is a function of y:
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y
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