Is this a book error? Can't figure it out...
"Consider the demand equation:
p = -.02x + 400 (0< x < 20,000) (greater than or equal to)
Solving the demand equation for x in terms of p we find:
x = f(p) = -50p + 20,000
I can't figure out how the second is derived from the first. Some guidance would be appreciated.