Beginning Algebra, 11th Edition

Approximate the length of a bass weighing 2.20 lb

and having girth 10 in. (Source: Sacramento

Bee.)

Given formula

Multiply by 1200.

Divide by 10.

Interchange the sides.

Square root property

A calculator shows that so the length of the bass is a little

more than 16 in. (We reject the negative solution , since Lrepresents

length.) NOW TRY

- 2264 L-16.25

2264 L16.25,

L= 2264

L^2 = 264

2640 = 10 L^2

2.20= w=2.20,g= 10

L^2 # 10

1200

w=

L^2 g

1200

SECTION 9.1 Solving Quadratic Equations by the Square Root Property 557

OBJECTIVE 4 Use formulas involving squared variables.

Finding the Length of a Bass

We can approximate the weight of a bass, in pounds, given its length Land its girth g,

both measured in inches, using the formula

w=

L^2 g

1200

.

EXAMPLE 6

Complete solution available
on the Video Resources on DVD

9.1 EXERCISES

Concept Check Match each equation in Column I with the correct description of its solution

in Column II.

III

1. A.No real number solutions


2. B.Two integer solutions


3. C.Two irrational solutions


4. D.Two rational solutions that are not integers

Solve each equation by the zero-factor property. See Example 1.

Solve each equation by using the square root property. Simplify all radicals. See Example 2.

11. 
    
    
    
    12. 
        
        
        
        13. 
            
        
        
        
        
    
    
    
    


12. 
    
    
    
    15. 
        
        
        
        16. 
            
        
        
        
        
    
    
    
    


13. 
    
    
    
    18. 19.x^2 =
    
    
    
    

25

4

x^2 =- 100 m^2 =- 64

m^2 = 22 t^2 = 48 x^2 = 54

x^2 = 81 z^2 = 169 x^2 = 14

x^2 = 144 3 x^2 - 13 x= 30 5 x^2 - 14 x= 3

x^2 - x- 56 = 0 x^2 - 2 x- 99 = 0 x^2 = 121

x^2 = 16

x^2 =

25

36

x^2 =- 9

x^2 = 12

NOW TRY
EXERCISE 6
Use the formula in Example 6
to approximate the length of a
bass weighing 2.10 lb and
having girth 9 in.

NOW TRY ANSWER
6.approximately 16.73 in.