Please help im stuck on this one and also explain

Which expression is equivalent to (3^2)^-2 a.-81 b.-12 c.1/81 d.1/12

Marco has $38.43 dollars in his checking account. his checking account is linked to his amazon music account so he can buy music. the songs he purchases cost $1.29. part 1: write an expression to describe the amount of money in his checking account in relationship to the number of songs he purchases. part 2: describe what the variable represents in this situation.

The longer leg of a 30° 60° 90° triangle is 16 times square root of three how long is a shorter leg