Melody

The meaning of this question is not clear 

$$\\(2a-b)^2\\
=(2a)^2-(2*2a*b)+(-b)^2$$

CAn you take it from there?

3

because 3*3*3=27

You could have given an example Tiddle  

3/4 is the same as 3 divided by 4  On just about any calc this will give you a decimal answer.

price divided  by number of units

OH anon this is a function it does not mean  f*x  

Good attempt though.     thumbs up for you :)

f(x)= (9(6)-1) - (9(2)-1)=53-17 = 36

Mmm

120mg

after one full day 60mg      {this is the end of the first day and the beginning of the second

So there will be 60mg left