Question #44ed3

1 Answer
Dec 18, 2017

The zeros occur at #x = -4# and #x = -7#. Please observe that we have discarded #x = -3# because it is one of the values that are not allowed.

Explanation:

Given:

#f(x) = (x^3+14x^2+61x+84)/(x^3+4x^2−69x−216) = 0#

Factor the denominator so that we may restrict the domain to prevent division by 0:

#f(x) = (x^3+14x^2+61x+84)/((x-8)(x+3)(x+9)) = 0#

This means that x must not equal #8,-3 or -9#

#f(x) = (x^3+14x^2+61x+84)/((x-8)(x+3)(x+9)) = 0;x !=8,-3,-9#

Factor the numerator:

#f(x) = ((x+3)(x+4)(x+7))/((x-8)(x+3)(x+9)) = 0;x !=8,-3,-9#

The zeros occur at #x = -4# and #x = -7#. Please observe that we have discarded #x = -3# because it is one of the values that are not allowed.