Which number when subtitubed for x makes this equation 4x 8 = 16 true?

The slope of a line is -1/2 . what is the slope of a line that is parallel to it? a. 1/2 b.2 c. -1/2 d. -2

Me because some of question i don’t understand

Omar is going on a road trip! the car rental company offers him two types of cars. each car has a fixed price, but he also needs to consider the cost of fuel. the first car costs $90 to rent, and because of its fuel consumption rate, there's an additional cost of s0.50 per kilometer driven.