The equation is .
Let .
Rational zeros method :
\Rational Root Theorem, if a rational number in simplest form is a root of the polynomial equation
, then
is a factor of
and
is a factor if
.
If is a rational zero, then
is a factor of
and
is a factor of
.
The possible factors of are
.
The possible factors for are
.
So, .
Consider .
Substitute in
.
.
Since ,
is not zero of
.
Consider .
Using synthetic division :
\
Since ,
is a zero of
.
Therefore, by factor theorem, .
The depressed polynomial of is
.
Consider .
Using synthetic division:
\
Since ,
is a zero of
.
The depressed polynomial is .
Solve by using quadratic formula. \ \
The solutions of equation in real number system are .
The solutions of equation in real number system are .