Question

5. What is the value of 9²-1
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Answer 1

Answer:

80

Step-by-step explanation:

9*9=81

81-1=80

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Answer 2

Answer:

81-1=80

by using the formula,

a²-b²=(a+b)(a-b)

9²-1²=(9+1)(9-1)

81-1=10×8

80=80

I hope this answer may help you