Question

What is x^4-10x^2+9 simplified

Answer 1

$\bf \textit{difference of squares} \\ \quad \\ (a-b)(a+b) = a^2-b^2\qquad \qquad a^2-b^2 = (a-b)(a+b)\\\\ -------------------------------\\\\ %x^4-10x^2+9 x^4-10x^2+9\implies (x^2)^2-10x^2+9\implies (x^2-9)(x^2-1) \\\\\\ \underline{(x^2-3^2)}(x^2-1^2)\implies \underline{(x-3)(x+3)}(x-1)(x+1)$

$\bf \textit{keep in mind that }1=1^2=1^3=1^5=1^{10}=1^{1000000}$