Question

Find the missing term in the following expression to make a perfect square.

`4x^2-square+49`

Answer 1

Using the identity,

a² − 2ab + b² = (a − b)²

We know that,

The first term is 4x² = (2x)²

⇒ a = 2x

And the last term is 49 = 7²

⇒ b = 7

Thus,

Finding the middle term,

2ab = 2 × 2x × 7

∴ 2ab = 28x

Hence, \[\ 4x^2-\boxed{28x}+49\]