Intermediate Algebra (11th edition)

(Marvins-Underground-K-12) #1
7.A formula from anthropology says that

.

Find Lif and.

8.The gravitational force between two
masses is given by

.

Find Mif , ,
m= 1 , and d= 3 * 10 -^6.

F= 10 G=6.67* 10 -^11


F=


GMm
c= 80 b= 5 d^2

c=

100 b
L

402 CHAPTER 7 Rational Expressions and Functions


NOTEThere is another way to approach problems about rates of work. In Example 8,


xrepresents the number of hours it will take the two people working together to com-


plete the entire job. In 1 hr, of the entire job will be completed. In 1 hr, Kareem


completes of the job and Letitia completes of the job.


The sum of their rates equals.

When each side of this equation is multiplied by 35x, the result is the


same equation we got in Example 8in the third line from the bottom. Thus, the solu-


tion of the equation is the same with either approach.


5 x+ 7 x=35,


1
x

1


7


+


1


5


=


1


x


1
5

1
7

1
x

Complete solution available
on the Video Resources on DVD


7.5 EXERCISES


Concept Check Exercises 1– 4 present a familiar formula. Give the letter of the choice that
is an equivalent form of the formula.


  1. ( percent)


A. B. C. D.


  1. (geometry)


A. B. C. D.


  1. ( physics)


A. B. C. D.



  1. (electricity)


A. B. C. D.


Solve each problem. See Example 1.

E= E=RI


I


R


R= R=IE


I


E


I=


E


R


F= F=ma

a
m

F=


m
a

a=mF

m=

F


a

W=


H


VL


L=


WH


V


L=


V


WH


H=


LW


V


V=LWH


p=

r
b

b=

r
p

r=

b
p

b=

p
r

p=br

5.In work with electric circuits, the formula

occurs. Find bif and.

6.A gas law in chemistry says that

.

Suppose that , , ,
P= 50 , and v= 8. Find p.

T= 300 t= 350 V= 9

PV


T


=


pv
t
a= 8 c= 12

1


a

=


1


b

+


1


c
Free download pdf