Have to slove for x

Acompany is testing in comparing to lightbulb designs the box plot shows the number of hours that each lightbulb design last before burning out which statement is best supported by the information of the plot

2x - 20 = 32 20 - 3x = 8 6x - 8 = 16 -13 - 3x = -10

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