Introductory
Example
Fill
the
Gas
Tank
Your
gas
tank
holds
12
gallons,
but
right
now
you're
running
on
empty.
As
you
pull
into
the
gas
station,
the
engine
sputters
and
dies—the
gas
tal:lk
is
completely
empty.
You
pump
12
gallons
into
the
tank
and
swipe
your
credit
card.
How
much
does
it
cost?
That
depends
on
the
price
of
gas,
of
course!
But
exactly
how
does
it
depend
on
the
price?
If
the
price
per
gallon
is
$3.40,
what
is
the
cost
to
fill
the
tank?
17.-%.407°40.80
$40.
70
If
the
price
per
gallon
is
$4.10,
what
is
the
cost
to
fill
the
tank?
12-4.10
=
449.2.0
$49.20
Fill
the
Gas
Tank:
Function
and
Symbolic
Form
The
symbolic
form:
Write
an
algebraic
expression
for
the
cost
price.
In
our
example:
to
the
consumer
in
terms
of
the
=1
meF%:lr%
This
is
read
as:
function
of
the
price
p
per
gallon.
The
cost,
K(p),
t0
fill
the
tank
is
a
Written
form:
of
$3.40
per
gallon
is
$40.80."
«"The
cost
of
filling
the
tank
at
a
price
e
ho
hQQd
For
Uhits
Symbolic
form:
k(3.40)=_40-80
36
