B is a square with a side length of x- 120, and c is a square with a side length of x- 120 m and a width of 120-(x- 120). The equation can be solved according to the area formula of rectangle.

Solution: According to the meaning of the question, (x-120) [120-(x-120)] = 3200,

x2-360x+32000=0，

The solution is x 1=200, X2 = 160.

X = 200 or x= 160.

Hope to adopt! ! !