Question

-12b^5-b^3+b factorise it​

Answer 1

$\sf - 12 {b}^{5} - {b}^{3} + b$

$\sf= b( - 12 {b}^{4} - {b}^{2} + 1)$

$\sf = b( - 12 {b}^{4} + 3 {b}^{2} - 4 {b}^{2} + 1)$

$= \sf b( - 3 {b}^{2} (4 {b}^{2} - 1) - (4 {b}^{2} - 1))$

$= \sf- b(4 {b}^{2} - 1)(3 {b}^{2} + 1)$

$\sf= - b(2b - 1)(2b + 1)(3 {b}^{2} + 1)$

And, over the Complex numbers

$\sf= - b(2b - 1)(2b + 1)( \sqrt{3} b - i)( \sqrt{3} b + i)$