On a trip that took 10 hours, mark drove 2 fewer hours than mary. how many hours did mary drive?

Pls , the question is in the picture!

Which sum or difference identity would you use to verify that cos (180° - ∅) = -cos ∅? a. sin (α -β) = sin α cos β – cos α sin β b. cos (α -β) = cos α cos β – sin α sin β c. cos (α -β) = cos α cos β + sin α sin β d. sin (α + β) = sin α cos β + cos α sin β

Add the fractions, and simply the result to lowest terms. 2/3 + 2/7= ?