Coefficient
The
coefficient of a quantity records how many of that quantity there are.
Since constants alone do not record the number of some quantity, they are not usually considered as numerical coefficients. For example, in the expression
, the coefficient of
is 7. (There are 7
x 's.)
is 2. (There are 2
y 's.)
is
. (There are
z 's.)
The constant 12 is not considered a numerical coefficient.
When the numerical coefficient of a variable is 1, we write only the variable and not the coefficient. For example, we write
rather than
. It is clear just by looking at
that there is only one.
Numerical evaluation
We know that a variable represents an unknown quantity. Therefore, any expression that contains a variable represents an unknown quantity. For example, if the value of
is unknown, then the value of
is unknown. The value of
depends on the value of
.
Numerical evaluation
Numerical evaluation is the process of determining the numerical value of an algebraic expression by replacing the variables in the expression with specified numbers.
Sample set b
Find the value of each expression.
, if
and
Replace
x with –4 and
y with 2.
Thus, when
and
,
.
, if
and
=
.
Replace
a with 6 and
b with –3.
Thus, when
a = 6 and
b = –3,
.
, if
and
Replace
with –5 and
with –1.
Thus, when
and
,
.
, if
Replace
x with 4.
Thus, when
,
.
, if
Replace
x with 3.
, if
.
Replace
x with 3.
The exponent is connected to –3, not 3 as in the problem above.
Practice set b
Find the value of each expression.
if
and
, if
,
,
, if
, and
, if
and
, if
and
, if
, if
, if
Exercises
In an algebraic expression, terms are separated by
signs and factors are separated by
signs.
For the following 8 problems, specify each term.
What is the function of a numerical coefficient?
Write
in a simpler way.
Write 1
s in a simpler way.
In the expression 5
a , how many
a ’s are indicated?
In the expression –7
c , how many
c ’s are indicated?
Find the value of each expression.
, if
and
, if
and
, if
,
, and
, if
,
,
, and
if
and
if
and
, if
and
, if
and
, if
and
, if
,
, and
if
,
, and
, if
,
,
, and
, if
and
, if
and
, if
and
, if
and
, if
, if
, if
if
, if
if
, if
if
Exercises for review
(
[link] ) Perform the addition:
.
(
[link] ) Arrange the numbers in order from smallest to largest:
(
[link] ) Find the value of
(
[link] ) Write the proportion in fractional form: “9 is to 8 as
x is to 7.”
(
[link] ) Find the value of