Answer:
15 days
Step-by-step explanation:
Don't you mean 1/3? If so,
5 cans
-------------------- = 15 days
1/3 can/daily
Using a calculator, you can find out that

and so that means

so your answer is
We can cosider this to be a difference of 2 squares so
4x^4 - 9x^2 = (2x^2 - 3x)(2x^2 + 3x) so D is one answer
also we could take x^2 out and get
x^2(4x^2 - 9) = C