Question

using identities,evalute:-(a)77² and (b) 78×82​

Answer 1

Step-by-step explanation:

$77^{2}$ = $(80)^{2}$-$(3)^{2}$

     =(80+3)(80-3)

     =83*77

     =6391

78×82​=(80-2)(80+2)

          =$(80)^{2}$-$(2)^{2}$

          =6400-4

          =6336

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HOPE IT HELPS................