The function is
.
Identify Possible Rational Zero:
\Usually it is not practical to test all possible zeros of a polynomial function using only synthetic substitution. The Rational Zero Theorem can be used for finding the some possible zeros to test.
\
.
Because the leading coefficient is
, the possible rational zeros are the intezer factors of the constant term
.
or
.
Therefore, the possible rational zeros of
are
.
The function is
.
Perform the synthetic substitution method by testing
and
.

Since
, conclude that
is a zero of
.
Therefore
is a rational zero.
The depressed polynomial is
.
Consider
.

or 
or
.
Therefore,
.
The final quotient can be written as
.
Factoring the quadratic expression
.
By using Factor theorem,
\When
then
is a factor of polynomial.
Factoring of
.
Zeros are
.
The possible rational zeros of
are
.
The rational zeros of
are
.