Question

Which of the following values of x makes the rational expression below undefined?
Problem : 16-x/7+x
A. 7
B. -7
C. 16
D. -16

Answer 1

B. -7
When the denominator equals zero, that makes it undefined

Answer 2

Answer:  The correct option is (B) -7.

Step-by-step explanation:  We are given to select the correct values of x that make the following rational expression undefined :

$E=\dfrac{16-x}{7+x}~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)$

We know that

a rational expression is undefined at the points where the denominator becomes zero.

Therefore, the expression (i) will become undefined when

$7+x=0\\\\\Rightarrow x=-7.$

Thus, the required value of x where the given expression is undefined is -7.

Option (B) is CORRECT.