The answer is D just so you know
X=27
81 = 3x= 27
So x means 27
Distance = speed rate x time
Speed rate = 120 miles per hour
Time = 3 hours
Replacing:
D = 120 mph x 3 h = 360 miles
Check the picture below.
recall that in a square, all sides are equal, so if we make b = a, then we get that for one side, also recall that the area of a rectangle is length*width, so in this case,
X=5
Do you need an explanation or is the answer enough?