$\"\"$

If $\"\"$ is a zero,then $\"\"$ is also zero according to Complex Conjugated theorem.

$\"\"$ are factors of the polynomial function.

The polynomial function as a product.

$\"\"$

Apply associative property of addition: $\"a$ .

$\"\"$ $\"\"$

Apply difference of two squares formula: $\"open$ .

$\"\"$

$\"equal$

$\"equal$ $\"\"$

$\"straight$ is a polynomial function of least degree with integral coefficients and zeros of $\"\"$ .