The function is
.
Identify Possible Rational Zeros
\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 integer factors of the constant term
.
Therefore the possible rational zeros of
are
.

Perform the synthetic substitution method by testing
.
is a rational zero.
The depressed polynomial is
.
.
Perform the synthetic substitution method by testing
.
is a rational zero.
Therefore
and
are factors of
.
The final quotient is
.
has no real zeros.
Rational zeros of
are
.
Possible rational zeros of
are
.
Rational zeros of
are
.