Which of the following values of x makes the rational expression below equal to zero? 2x+16/x+5 a. 5 b. -5 c. 8 d. -8

2x + 16 / x + 5
 For this case what you should know is that an indefinite expression are those in which mathematically no numerical value can be obtained.
 We have then that a division between zero causes an expression to be undefined.
 For x = -5 we have:
 (2 (-5) +16) / ((- 5) +5)
 (-10 + 16) / (- 5 + 5) = 6/0 (undefined)
 
 x = -5
 b. -5