Jana ran the first 312 miles of a 5-mile race in 13 hours. What was her average rate, in miles per hour, for this first part of the race? Explain how you solved the problem.

speed = distance / time

Jana's speed is

  speed = (3.5 mi)/(1/3 h) = 3*3.5 mi/h = 10.5 mi/h

problem:

f(x) = - 2/3x + 5; f(5/2)

substitute 5/2 in for x:

f(5/2) = -2/3(5/2) + 5

simplify the right side:

f(5/2) = -5/3 + 5

f(5/2) = 10/3

f(5/2) = 10/3

i hope this !

-22

times both sides by 2, times () by 8, add alile terms, move terms, add alike and caculate divide both sides by 3