p² + 6p + 8

Here, coefficient of p² is unity so we add and subtract square of half of coefficient of p

Therefore,

p² + 6p + 8 = p² + 6p + 3² – 3² + 8 (Adding and subtracting 3²)

= (p + 3)² – 1² (By completing the square)

= (p + 3 – 1) (p + 3 + 1)

= (p + 2) (p + 4)