Answer:
To solve for n you need to get it by itself
First you want to distribute your 2 through the (3n+14)
-2n+6n+28=-20 (2*3n+2*14= 6n+28)
Now you want to combine any like terms if possible
4n+28=-20 (-2n+6n=4n, both like terms)
Then you want to subtract -28 from both sides
4n=-48 (28-28=0, -20-28=-48)
Lastly you want to divide both sides by 4
n=-12 (4n/4=n, -48/4= -12)
In order to find the answer you will have too divide 58 by 18 and then divide what you get from that by 100 to get your answer.
100%/x%=58/18
(100/x)*x=(58/18)*x
100=3.22222222222*x
(3.22222222222) to get x
100/3.22222222222=x
x=31.0344827586
Therefore your answer is "31%."
Hope this helps.
The order of the 3 books does not matter so its the number of combinations of 3 from 45
b is the correct choice