1. The combined volume of all the tanks at the aquarium is written in Scientific notation. Keeping this on mind, you can write it as following:

2. Now, you must sum the combined volume of all the tanks and the volume of the new tank to calculate the total volume of all of them:
3. Now, you can write the result in Scientific notation, as following:

The answer is: 
I) -7s^2+28st+21su
II) -8c^2+20cd
30 x 0.05 = $1.5 is the answer
Answer:
K=26
Step-by-step explanation: