Just help quick please its easy but im dumb

For f(x)=2x+3 and g(x)=x^2- 8 find (f+g) (x)

∆red ≅ ∆ by rule will give brainiest if possible

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