The function is
.
The factors are
and
.
Perform the synthetic division method to test each factor.
\Synthetic division for factor
.
Rewrite the division expression so that the divisor is in the form of
.
The obtained divisor is
.
Now the divisor is in the form of
.

.

When
is divided by
, the remainder is
.
So
is a factor of
.
The depressed polynomial is
.
The obtained depressed polynomial is
.
Now test the second factor
with the depressed polynomial
.
Synthetic division for factor
.
When
is divided by
The remainder is
.
So
is not a factor of
.
Since
is a factor of
, the quotient in factored form is 

.
The obtained depressed polynomial is
.
Perform the synthetic substitution method by testing
.
Since
, conclude that
is a zero of
.
Therefore,
is a rational zero.
Therefore,
and
are the factors of
.
The remaining quadratic expression
can be written as
.
The quotient can be written in the factored form as 

or
.
is a factor of
.
is not a factor of
.
The factored form of
or
. \ \