Question

find all the zeros of the quadratic function.
$y=x^{2}-4x-21$
if there is more than one zero, separate them with commas.
if there are no zeros, click on
one\.
zero(s):

Explanation:

Step1: Set function equal to 0

$x^2 - 4x - 21 = 0$

Step2: Factor the quadratic

$(x - 7)(x + 3) = 0$

Step3: Solve for x

$x - 7 = 0 \implies x=7$; $x + 3 = 0 \implies x=-3$

Answer:

7, -3