16. The original price of a tie is $12.50. The new price of the tie is now $7.50. By what percentage was the tie marked down? *

The given  0 = x + 2 + x2 can and should be re-written as  0 = 1x^2 + 1x   + 2.   thus, a=1, b=1 and c=2.   the discriminant is b^2-4ac, or 1^2-4(1)(2), or1-8=-7.because the discriminant is negative we have two complex roots.