Help pls

X+ y = 5 ; x - y =3 solve using linear combination

Kyle and elijah are planning a road trip to california. their car travels 3/4 of a mile per min if they did not stop driving, how many miles could kyle and elijah drive in a whole day? ? 1 day = 24 hours. plzzz i will give you 100 points

For f(x) = 3x+1 and g(x) = x2 - 6, find (g/f)(x)