Log base 8 12 equals x - 2

Pls! does anybody know a shortcut for answering these types of questions in the future?

Aclothing store has the sign shown in the shop window. pani sees the sign and wants to buy 3 shirts and 2 pairs of jeans. the cost of each shirt before the discount is $12, and the cost of each pair of jeans is $19 before the discount. write and simplify an expression to find the amount pani pays if a $3 discount is applied to her total

Olga bought a new skirt that cost $20. sales tax is 5%. how much did olga pay, including sales tax? 7.