$\"\"$

The equation is $\"\"$ .

Find the number of posible real zeros and turning points.

Consider the equation $\"\"$ .

The degree of the function is $\"\"$ ,hence the function have at most four real zeros and three turning poins.

Find all the real zeros by factorize the function.

Factorise the function $\"\"$ by equating $\"\"$ .

$\"\"$

$\"\"$ and $\"\"$

Hence the real zeros are $\"\"$ and $\"\"$ .

$\"\"$

The degree of the function is $\"\"$ ,hence the function have at most four real zeros and three turning poins.

The real zeros are $\"\"$ and $\"\"$ .