Pls help! will give brainlist!

using substitution, what is the solution for the system of equations below?

A. (2,5)
B. (2,31)
C. (2,4)
D. (5,2)

Asurvey of 2,000 doctors showed that an average of 3 out of 5 doctors use brand x aspirin. how many doctors use brand x aspirin

Cody started biking to the park traveling 15 mph, after some time the bike got a flat so cody walked the rest of the way, traveling 4 mph. if the total trip to the park took 6 hours and it was 46 miles away, how long did cody travel at each speed? solve using rate times time= distance

Check all that apply. f is a function. f is a one-to-one function. c is a function. c is a one-to-one function.