Yesterday the temperature at noon was 11.4°f by midnight the temperature had decreased by 15.7° what was the temperature at midnight

How do i do this activity, is appreciated

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)

Aconstruction worker has rope 9 m long he needs to cut it in pieces that are each 3 /5 m long how many such pieces can he cut without having any rope leftover?