For example, see ?⁴ – ?⁴ as (?²)² – (?²)², thus recognizing it as a difference of squares that can be factored as (?² – ?²)(?² + ?²) and further factored (? – ?)(? + ?)(? – ??)(? + ...

For example, see ?⁴ – ?⁴ as (?²)² – (?²)², thus recognizing it as a difference of squares that can be factored as (?² – ?²)(?² + ?²) and further factored (? – ?)(? + ?)(? – ??)(? + ??).