Please help and I’ll mark brain list!

Which is the most efficient first step to solve x in the equation 3.7x - 18 = -4.3x -34 a. add 3.7x to both sides of the equation. b. add 4.3x to both sides of the equation. c. subtract 18 from both sides of the equation. d. subtract 34 from both sides of the equation.

How many $20 bills do you need to have to make $280

Sasha drank 8 bottles of water everyday for a week. how many bottles of water did she drink in total?