Evaluate {(7.8)2 – (2.2)2}.

Question

Evaluate {(7.8)2 &ndash; (2.2)2}.

Philoid · Accepted Answer

We have,

{(7.8)2 &ndash; (2.2)2}

By using the formula a2 &ndash; b2 = (a + b)(a &ndash; b)

We get,

{(7.8)2 &ndash; (2.2)2} = (7.8 + 2.2)(7.8 &ndash; 2.2)

= (10 &times; 5.6)

= 56

So,

{(7.8)2 &ndash; (2.2)2} = 56

Evaluate {(7.8)² – (2.2)²}.