To solve this problem you must apply the proccedure shown below:
1. You have the following expression given in the problem above:
√(-4x) =100
2. Then, you have to clear the variable x, as below:
√(-4x) =100
(√(-4x))^2 =(100)^2
-4x=10000
x=10000/-4
3. Then, the result is:
x=-2500
4. Therefore, as you can see, the correct answer is first option (option a), which is:
a. x=-2500