Question

x⁴ – 625

Answer 1

$$\begin{gathered} x^4-625 \\ ={\left(x^2\right)}^2-{25}^2 \\ =\left(x^2+25\right)\left(x^2-25\right)\left[a^2-b^2=\left(a+b\right)\left(a-b\right)\right] \\ =\left(x^2+25\right)\left(x^2-5^2\right) \\ =\left(x^2+25\right)\left(x+5\right)\left(x-5\right)\left[a^2-b^2=\left(a+b\right)\left(a-b\right)\right] \end{gathered}$$