Question

find the value of 77 x 83 by using formula​

Answer 1

Answer:

77×83= (80-3)×(80+3)

now (a-b)(a+b)=

a ^{2} - b ^{2}a

2

−b

2

therefore the answer is 80^2-3^2

6400-9=6391

Answer 2

Answer:

(a+b) (a-b)

=77=80-3

=83=80+3

=(80+3) (80-3)

=a²-b²

=(80)²-(3)²

=6400-9

=6391