How do you solve such a question (1 1/2)^-3 asap

Ican figure out 20 shares multiply by $117.98 =2359.6920 shares multiply by $124.32=2486.40then take 40 shares multiply by $128.48=5139.20after that i'm lost any be greatly appreciated.

Sweet t saved 20 percent of the total cost of the green-eyed fleas new album let there be fleas on earth. if the regular price is $30 how much did sweet save

Which pair of expressions is equivalent? a 7(1–k)and7–k b 7(1–k)and1–7k c 7(1–k)and7–k d 7(1–k)and7–7k