Evaluate {(7.8) 2 – (2.2) 2 }.

Question

Evaluate {(7.8) 2 &#x2013; (2.2) 2 }.

Philoid · Accepted Answer

We have,

{(7.8)² – (2.2)²}

By using the formula a² – b² = (a + b)(a – b)

We get,

{(7.8)² – (2.2)²} = (7.8 + 2.2)(7.8 – 2.2)

= (10 × 5.6)

= 56

So,

{(7.8)² – (2.2)²} = 56