Find whether the trinomial is a perfect square or not :

x² + 14x + 49

x² + 14x + 49

Using the formula

[∵ (x + y)² = x²+ 2xy + y² ]

= x² + 2 $\times$ 7 $\times$ x + (7)²

= (x + 7)²

Hence, x² + 14x + 49 is a perfect square.