No work free points ;) thx
You can write it as 721 over 1000, then simplify from there
Because the left side of the equation is an absolute value, making it impossible to = to -1.
Area of triangle = 1/2 bh
60 = 1/2 (15) h
8 = h
Quadrilateral area = h x (b1 + b2)/2 = 8 x (15+9)/2 = 96 sq units
96 -60 = triangle BAD area = 36 sq units
R=-1/800(x^2-2400x)
use R'=0
R'=1/400x-300, 1/400x=300 => x=1200 critical point
take R(1200), we know its max bcuz of the orientation of R