Question

W4-21w2-100 how do you factor this

Answer 1

`\bf \textit{difference of squares} \\ \quad \\ (a-b)(a+b) = a^2-b^2\qquad \qquad a^2-b^2 = (a-b)(a+b)\\\\ -------------------------------\\\\ w^4-21w^2-100\implies (w^2)^2-21w^2-100\implies (w^2-25)(w^2+4) \\\\\\ (w^2-5^2)(w^2+4)\implies (w-5)(w+5)(w^2+4)`