Question

Simplify using identity: 279 x 279 - 21 x 21

Answer 1

Answer:

Step-by-step explanation:

We know that  

$a^{2} - b^{2} = (a+b)(a-b)$

So this question can be written as

$279^{2} - 21^{2}$ = (279 + 21) (279 - 21)

                = (300)(258)

                = 77400

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Answer 2

Answer:

very easy

Step-by-step explanation:

279×279-21×21

=77,841-21×21

=77,841-441

=77,400

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