Y =7 -3x is it linear or non linear?

Two cars which are 40 miles apart start moving simultaneously in the same direction with constant speeds. if the speed of the car which is behind is 56 mph and the speed of the other car is 48 mph, how many hours will it take for the car which is behind to catch up the car ahead of it?

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ah=4 and hc=1, find bh.

Using the figure below, select the two pairs of alternate interior angles.a: point 1 and point 4 b : point 2 and point 3 c: point 6 and point 6d: point 5 and point 7