Question

2 Points

For what values of x is the rational expression below undefined?
Check all that apply.
x-7
2x2 - 32
DA. 7
B. 4
D C.-7
OD. -2
0 E. -4
F. 2

Answer 1

B and e idk what I’m doing I thinking’s about deleting this dumb app

Answer 2

B and E

Explanation:

Given the rational expression

`(x-7)/(2x^2-32)` ← factorise the denominator

2x² - 32 ← take out a common factor of 2 from each term

= 2(x² - 16) ← (x² - 16) is a difference of squares

= 2(x - 4)(x + 4)

The expression can now be written as

`(x-7)/(2(x-4)(x+4))`

The denominator of the expression cannot be zero as this would make the expression undefined. Equating the denominator to zero and solving gives the values that x cannot be.

2(x - 4)(x + 4) = 0

Equate each factor to zero and solve for x

x - 4 = 0 ⇒ x = 4

x + 4 = 0 ⇒ x = - 4

These are the values of x that make the expression undefined.

x = 4 → B

x = - 4 → E