Please help with pre-cal

Question

A rancher has 200ft of fencing to enclose 2 adjacent rectangular corrals (a) write the area of corrals as a function of x

Answer 1

200 feet total fencing

2 adjacent corrals, rectangular

with 3 sides =x

other 2 perpendicular sides = (200-3x)/2

total area = x(200-3x)/2 = 100x -1.5x^2