Question

Identify the domain of the following rational expression:

7x/3x+15
O All real numbers except 5.
O All real numbers except 15.
O All real numbers except - 15.
O All real numbers except - 5.

Answer 1

Answer: D

Explanation:

The domain of a function is the allowed 'x' values that the function can take on and produce a defined 'y' value. We can ignore the numerator since it will never be undefined. The denominator on the other hand has a singularity when it equals zero. The reason for this is because we cannot divide by zero. Therefore, lets set the denominator to zero and find which 'x' value makes the function undefined:

`3x+15=0`

`3x=-15`

`x=-5`

Every single real 'x' value will work besides when x = -5. Therefore the answer is D