Question

Which expression is equivalent to 9^-2?
–81
–18
1/81
1/18

Answer 1

(9)^-2 = (1/9)^2 = 1/81

Answer 2

(C)
`f(x)={(1)/(81)}`

Explanation:

The given expression is:

`f(x)=9^-2`

Upon solving the above expression, which can be written as:

`f(x)=({(1)/(9)})^2`

`f(x)={(1)/(81)}`

which is same as the expression given in the option (C) that is
`f(x)={(1)/(81)}`, hence the option C is correct.