Question

For what value of x is the rational expression below equal to zero?

(x+5)(x - 1)
A. 4
ОО
B. 1
C. -5
d
D. -4
SUBMIT

Answer 1

I can only guess that by x^2-2x-24 you mean the entire denominator. In cases like this is is important to use parentheses to remove any doubts. For example:

(x+8) / (x^2-2x-24).

This rational expression is undefined at any x for which the denominator, x^2-2x-24, is zero.

x^2-2x-24 factors into (x+4)(x-6). The roots are -4 and +6.

Thus, the given expression is undefined at {-4,6} (set notation).

Explanation: