Answer
$x=1235$
Work Step by Step
"The distance by road from Cincinnati, Ohio, to Denver Colorado, is 71 miles less than the distance from Denver to San Francisco, California. If the total of these two distances is 2399 miles, find the distance
from Denver to San Francisco."
x is the distance from Denver to San Francisco
x-71 is the distance from Cincinnati to Denver
total distance is 2399
$x+x-71=2399$
add 71 on both sides
$ x+x=2399+71$
simplify
$ 2x= 2470$
divide both sides by 2
$x=1235$