Answer:
A. 3rd equation
B. 1st equation
C. 4th equation
D. 2nd equation
The final value within the square root can't be negative or else the solution is imaginary, and you also cannot divide by a value of zero.
Answer: 
Step-by-step explanation:

Volume without holes = 3 x 6 x 11 = 198 cubic inches.
Calculate volume of one hole:
3.14 x 0.5^2 x 3 = 2.355 cubic inches
There are 3 holes: 3 x 2.355 = 7.065
Subtract volume of the holes from the brick:
198 - 7.065 = 190.935 cubic inches.
Rounded to the nearest tenth: 190.9 cubic inches.
There is 1 solution x=-10