Please help equation

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

Asurvey of 45 teens found that they spent an average of 25.6 hours per week in front of a screen (television, computer, tablet, phone, based on the survey’s sample mean, which value could be the population mean? 2.3 hours 27.4 hours 75.3 hours 41.5 hours

Do,h = (7, 9) (14, 18) the scale factor is