Question

What are the excluded values of x for x^2-9x/ x^2 -7x-18

?
O x = -9, x = 2
O x = -9, x = 0
Ox= -2, x = 9
O x=0, x= 9

Answer 1

3rd option

Explanation:

the denominator cannot be zero as this would make the expression undefined.

equating the denominator to zero and solving gives the values that x cannot be.

x² - 7x - 18 = 0 ← in standard form

(x - 9)(x + 2) = 0 ← in factored form

equate each factor to zero and solve for x

x - 9 = 0 ⇒ x = 9

x + 2 = 0 ⇒ x = - 2

then

x = - 2, x = 9 ← are the excluded values