Question B.4.7: Factoring completely Factor each polynomial completely. a. 2...
Factoring completely
Factor each polynomial completely.
a. 2 w^{4}-32 b. -6 x^{7}+6 x
Learn more on how we answer questions.
a. 2 w^{4}-32=2\left(w^{4}-16\right) Factor out the greatest common factor.
=2\left(w^{2}-4\right)\left(w^{2}+4\right) Difference of two squares
=2(w-2)(w+2)\left(w^{2}+4\right) Difference of two squares
The polynomial is now factored completely because w^{2}+4 is prime.
b. -6 x^{7}+6 x=-6 x\left(x^{6}=1\right) Greatest common factor
=-6 x\left(x^{3}-1\right)\left(x^{3}+1\right) Difference of two squares
=-6 x(x-1)\left(x^{2}+x+1\right)(x+1)\left(x^{2}-x+1\right) Difference of two cubes; sum of two cubes
The polynomial is factored completely because all of the factors are prime.