Question

The value of 9² – 1 is equal to:

a. 81

b. 80

c. 79

d. none of the above​

Answer 1

$Value \: of \: 9^{2} - 1$

$= 9^{2} - 1^{2}$

/* By algebraic identity */

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

$= (9 +1 )( 9 - 1 )$

$= 10 \time 8$

$= 80$

Therefore.,

$Option \: \pink{ ( b ) } \: is \: correct$

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Answer 2

Answer:

80 (b)

Step-by-step explanation: