Find The value of each variable?

You paid 28.00 for 8 gallons of gasoline. how much would you pay for 15 gallons of gasoline?

Marcus and cody both leave the park at the same time, but in opposite directions. if cody travels 6 mph faster than marcus and after 4 hours they are 64 miles apart, how fast is each traveling? solve using rare times time = distance.

Which statement is true about the extreme value of the given quadratic equation? a. the equation has a maximum value with a y-coordinate of -21. b. the equation has a maximum value with a y-coordinate of -27. c. the equation has a minimum value with a y-coordinate of -21. d. the equation has a minimum value with a y-coordinate of -27.