Question

What are the zeros ?

Answer 1

Zeroes are found by factoring.  This is a quadratic and there are many aspects of a quadratic that are so helpful in so many ways.  But here we will just factor.  The best and most reliable way is to use the quadratic formula, but it's not totally necessary with this one.  We just need to find 2 numbers that add up to +1 and multiply to -20.  That would be +5 and -4.  5-4 = 1 and 5*-4 = -20.  By the Zero Product Property, (x + 5) = 0 or (x - 4) = 0.  Setting each one of those equal to 0, we have x + 5 = 0 and x = -5, and x - 4 = 0 and x = 4.  So the zeros are -5 and 4, choice B.