s = standard version amount
h = high quality version amount
we know that there were 1090 downloads of the song, meaning s + h = 1090.
we also know that the total amount of MBs downloaded was 3353 MBs, and since the standard is 2.1 MBs and the high quality is 4.9MBs, then 2.1s + 4.9h = 3353.
We are given :
Step 1: factor the part inside square root
The function given inside square root is of quadratic form.
So let us try to factorise it using AC method.
Here A*C = 4*25 = 100
so we have to find factors of 100 that add up to give -20.
the two factors are -10 and -10.
Rewriting the function :
=
=
=
Step 2:
Now we take square root of the factorised form
=
Answer : (2x-5)