Algebra 1 Common Core Student Edition, Grade 8-9

Challenge For Exercises 47-49, each expression represents the side length of a cube. Write

a polynomial in standard form for the surface area of each cube.

47. 
    

    x + (^2) 48. 3a + 1 49. 2c2 + 3
    4

    
    


48. 
    

    Financial Planning Suppose you d ep o sit $1500 for college in a savings account
    th at has an an n u a l interest rate r (expressed as a decim al). At th e en d of 3 years, the
    value of your acco u n t will be 1500(1 + r)3 dollars.
    a. Rewrite th e expression 1500(1 + r)3 by finding th e p ro d u c t
    1500(1 + r) (l + r) (l + r). W rite your answ er in s tan d ard form.
    b. How m u ch m oney is in th e ac co u n t after 3 yr if th e interest rate is 3% p e r year?

    
    

Apply What You've Learned

Look back at th e inform ation on page 485 ab o u t a com m unity garden. Kelly's

a n d R oberto’s plans for th eir original plots are show n again below. In th e Apply

W hat You’ve L earned in Lesson 8-1, y ou w rote b inom ials for the length an d

w idth of Kelly's plot.

Roberto's Plan

MATHEMATICAL

PRACTICES

MP2, MP3

Kelly's Plan

1 ft f

xft

xft

3ft 3ft

1 ft

1.5 ft

xft

ft

3ft

X

3ft

1.5 ft

a. Use a p ro d u c t of two binom ials to find a polynom ial th a t rep resen ts th e area of

Kelly’s plot.

b. Use a p ro d u c t of two binom ials to find a polynom ial th a t re p resen ts th e area of

Roberto’s plot.

c. Explain how you can use a specific value of x to check th a t you found th e products

in parts (a) and (b) correctly.

d. Based on th e polynom ials you w rote in p arts (a) a n d (b), can you conclude th a t the

area of Roberto's plot is greater th a n th e area of Kelly’s plot for any value of x? Give

an arg u m en t to su p p o rt your answer.

c

PowerAIgebra.com Lesso n 8-3 M u lt ip l yin g Bin o m i als 503