Question

What would be the irreducible factor form of $z^3-z$?

• A. $z(z^2-1)$
• B. $z^2(z-z^{-1})$
• C. $z(z-1)(z+1)$
• D. $z^3(1-z^{-2})$

Answer 1

The correct option is C $z(z-1)(z+1)$

$z^3-z$
Taking out 'z' as common factor, we get
$=z(z^2-1)$
Now we know that $(a^2-b^2)=(a+b)(a-b)$
$z(z^2-1)=z(z+1)(z-1)$