Section 1.4
S
olving Abs
olute Va
lue Equations
33
In Exercises 31−34, write an absolute v
alue equation
that has the given solutions.
31.
x
8 and
x
18
32.
x
6 and
x
10
33
.
x
2 and
x
9
34.
x
10 and
x
5
In Exercises 35−44, solve
the equation. Check yo
ur
solutions.
(
See Examples 4, 5, and 6.)
35
.
4
n
15
n
36.
2
c
+
8
10
c
37
.
2
b
9
b
6
38.
3
k
2
2
k
+
2
39.
4
p
3
2
p
+
8
40.
2
4
w
1
3
4
w
+
2
4
1
.
3
h
+
1
7
h
42.
6
a
5
4
a
43.
f
6
f
+
8
44.
3
x
4
3
x
5
45.
MODELING WITH
MA
THEMA
TICS
Starting from
300 feet awa
y,
a car driv
es tow
ard you. It then passes
by you at a speed of 48 feet per second. The distance
d
(in feet) of the car from you after
t
seconds is giv
en
by the equation
d
300
48
t
.
At what times is the
car 60 feet from you?
46.
MAKING AN ARGUMENT
Yo
ur friend says that the
absolute va
lue equation
3
x
+
8
9
5 has no
solution because the constant on the right side of the
equation is negati
ve.
Is your friend correct? Explain.
47.
MODELING WITH
MA
THEMA
TICS
Yo
u randomly
survey s
tudents about year-round school.
The results
are shown
in the graph.
Y
ear
-Round School
Oppose
Favor
0%
20%
40%
60%
80%
32%
Error:
±
5%
68%
The error giv
en in the graph means that the actual
percent could be 5% more or 5% less than the percent
reported by the surve
y.
a.
Write and solv
e an absolute v
alue equation to
nd
the least and greatest percents of students who
could be in fav
or of year
-round school.
b.
A classmate claims that
1
—
3
of the student body is
actually in fav
or of year
-round school. Does this
con
ict w
ith the survey
data? Explain.
48.
MODELING WITH
MA
THEMA
TICS
The recommended
weight of a soccer ball is 430 grams. The actual
weight is allo
wed to v
ary by up to 20 grams.
a.
Write and solve an absolute
value eq
uation to
nd t
he
minimum and maximum
acceptable soccer ball weights.
b.
A soccer ball weighs 423 grams.
Due to wear and tear,
the weight of
the ball decreases by 16 grams. Is the
weight acceptable? Explain.
ERROR ANAL
Y
SIS
In Exercises 49 and 50, describe and
correct the err
or in solving the equation.
49.
2
x
−
1
=
−
9
2
x
−
1
=
−
9
or
2
x
−
1
=
−
(
−
9)
2
x
=
−
8 2
x
=
10
x
=
−
4
x
=
5
T
he solut
ions are
x
=
−
4 and
x
=
5.
✗
50.
5
x
8
=
x
5
x
8
=
x
or
5
x
8
=
−
x
4
x
8
=
0
6
x
8
=
0
4
x
=
−
8 6
x
=
−
8
x
=
−
2
x
=
−
4
—
3
T
he solut
ions are
x
=
−
2 and
x
=
4
—
3
.
✗
51.
ANAL
YZING EQU
A
TIONS
W
ithout solving completely
,
place each equation into one of the three categories.
No
solution
One
solution
Two
solutions
x
2
+
6
0
x
+
3
1
0
x
+
8
+
2
7
x
1
+
4
4
x
6
5
9
x
+
5
8
8
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