Section 2-8 - Flash (Medium) - 20120130 09.49.11AM
X
Solving for a specific variable
Example #1: Solve each equation for the variable indicated
Example #1: Solve each equation for the variable indicated
Example #1: Solve each equation for the variable indicated
Example #1: Solve each equation for the variable indicated
Extra Example #1: Solve each equation for the variable indicated
Extra Example #1: Solve each equation for the variable indicated
Example #2: write an equation and then solve for the specified variable.
EXTRA Example #3: a car’s fuel economy E (miles per gallon) is given by the formula E=m/g, where m is the numbers of miles and g is the number of gallons of fuel used.
Example #3: The formula for the volume of a cylinder is V= r2 h, where the r is the radius of the cylinder and the h is the height.
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Solving
for
a
specific
variable
*I
can
solve
an
equation
for
a
specific
variable.
*I
can
use
the
distributive
property
to
solve
an
equation
for
a
specific
variable.
*I
can
solve
for
a
variable
in
a
real
world
problem.
Example
#1:
Solve
each
equation
for
the
variable
indicated
12x
+
5
=
y
for
x
(get
x
by
alone)
-5
-5
12x
=
y
–
5
12
12
x
=
y
–
5
12
12
Example
#1:
Solve
each
equation
for
the
variable
indicated
5b
+
12c
=
9
for
b
(get
b
alone)
-12c
-12c
5b
=
9
-
12c
5
5
b
=
9
–
12c
5
5
Example
#1:
Solve
each
equation
for
the
variable
indicated
8(c
–
6)
=
r
for
c
(get
c
alone)
8c
–
48
=
r
+48
+48
8c
=
r+
48
8
8
8
c
=
r
+
6
8
Example
#1:
Solve
each
equation
for
the
variable
indicated
k
–
2
=
11m
for
k
(get
k
alone)
5
*5
*5
K
–
2
=
55m
+2
+2
K
=
55m
+
2
Extra
Example
#1:
Solve
each
equation
for
the
variable
indicated
7x
–
2z
=
4
–
xy
for
x
(
get
all
x’s
together
and
alone)
+2z
+2z
7x
=
4
–
xy
+2z
+xy
+xy
7x
+xy
=
4
+2z
x
(7
+
y)
=
4
+
2z
7
+
y
7
+
y
x
=
4
+
2z
7
+
y
Extra
Example
#1:
Solve
each
equation
for
the
variable
indicated
d
+
5c
=
3d
–
1
for
d
(get
the
d’s
together
and
alone)
-5c
-5c
d
=
3d
–
1
–
5c
-3d
-3d
-2d
=
-1
-5c
-2
-2
d
=
1
+
5c
2
2
Example
#2:
write
an
equation
and
then
solve
for
the
specified
variable.
Eight
more
than
a
number
w
is
five
less
than
twice
a
number
x.
(solve
for
w).
8
+
w
=
2x
–
5
-8
-8
w
=
2x
-
13
Three
times
a
number
p
is
two-fifths
of
a
number
g.
(solve
for
g).
3p
=
2/5g
*5/2
*5/2
(3
*
5=
15,
1
*
2=
2
giving
15/2)
7.5p
=
g
EXTRA
Example
#3:
a
car’s
fuel
economy
E
(miles
per
gallon)
is
given
by
the
formula
E=m/g,
where
m
is
the
numbers
of
miles
and
g
is
the
number
of
gallons
of
fuel
used.
a.
Solve
the
formula
for
m.
E
=
m
g
*g
*g
Eg
=
m
b.
If
Carrie’s
car
has
an
average
fuel
consumption
of
30
miles
per
gallon
and
she
used
9.5
gallons,
how
far
did
she
drive?
Eg
=
m
E=30
g=9.5
m
=
30
*
9.5
m=285
285
miles
Example
#3:
The
formula
for
the
volume
of
a
cylinder
is
V=
r2
h,
where
the
r
is
the
radius
of
the
cylinder
and
the
h
is
the
height.
a.
Solve
the
formula
for
h.
V
=
r2
h
r2
r2
V
=
h
r2
b.
What
is
the
height
of
a
cylindrical
swimming
pool
that
has
a
radius
of
12
feet
and
a
volume
of
1810
ft3?
r=12
V=1810
=3.14
h
=1810
3.14*122
h
=4
4
feet