f(x) = (x + 3)(x - 5)
x = -3 and
x = 5 make
The above answer was easy because
f(x) was factored.
The answer is less obvious for
f(x) = x2 - 2x - 15
Of course, in general, the coefficients are not integers, which makes the problem even more difficult (unless you have a calculator):
g(x) = 4.592x2 + 2.308x - 8.083
Fortunately, the quadratic formula provides a way to find the roots. If the quadratic is
ax2 + bx + c
then the formula gives your the roots, if any.
(Math Review:) Will there be two roots for every choice of