What is Everyone up to??? Which of the purchases would be the least expensive?

Purchase
Amount of sale
Sales tax rate
A
$150
5%
B
$145
7%
C
$140
8%
D
$135
9%

purchase A
purchase B
purchase C
purchase D

Each month, a shopkeeper spends 5x + 14 dollars on rent and electricity. if he spends 3x−5 dollars on rent, how much does he spend on electricity? for which value(s) of x is the amount the shopkeeper spends on electricity less than $100? explain how you found the value(s).

Aye asap pls ! markin da brainiest too ! btw da step choices are all add, distribute, divide, n subtract

Kelli swam upstream for some distance in a hour.she then swam downstream the same river for the same distance in only 6 minutes.if the river flows at 5km/hr, how fast can kelli swim in still water?