Answer: 
Step-by-step explanation:
Let be "x" the original volume of the solution (in milliliters) before the acid was added and "y" the volume of the solution (in milliliters) after the addition of the acid.
Set up a system of equations:

Applying the Substitution Method, you can substitute the second equation into the first equation and then solve for "x":
Answer:
D.
Step-by-step explanation:
That is the answer. The complex numbers have opposite real parts.
The answer is 32cm :))))))
9b - 12b² factorised would be 3b(3 - 4b).
You can find this as you must first find a common factor between 9b and -12b², which would be 3b. We can then take this out of the bracket and divide both terms by 3b to get the final answer, which leaves us with 3b(3 - 4b).
I hope this helps!