Factories the following

l² – (m – n)²

In the given expression l² – (m – n)²

Both terms are perfect square

⇒ l² = l × l

⇒ (m – n)² = (m – n) × (m – n)

∴ l² – (m - n)² Seems to be in identity a²-b² = (a + b)(a-b)

Where a = a and b = (m - n);

∴ l² – (m – n)² = (l + m-n)(l-m + n)

Hence the factors of l²–(m–n)²are (l + m-n)(l-m + n)