Answer:
Step-by-step explanation:
Given that a solution containing 12% alcohol is to be mixed with a solution containing 4% alcohol to make 20 gallons of solution containing 9% alcohol.
Let x gallons of 12% alcohol be mixed with y gallons of 4% alcohol.
Total gallons
Alcohol content in the total mixture 

b) Two equations are

c) This is of the form Ax = B
where A =![\left[\begin{array}{ccc}1&1\\12&4\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%261%5C%5C12%264%5Cend%7Barray%7D%5Cright%5D)
Inverse is ![\frac{1}{4-12} \left[\begin{array}{ccc}4&-1\\-12&12\end{array}\right]\\=\frac{-1}{8} \left[\begin{array}{ccc}4&-1\\-12&12\end{array}\right]\\](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B4-12%7D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D4%26-1%5C%5C-12%2612%5Cend%7Barray%7D%5Cright%5D%5C%5C%3D%5Cfrac%7B-1%7D%7B8%7D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D4%26-1%5C%5C-12%2612%5Cend%7Barray%7D%5Cright%5D%5C%5C)
Solution set is A inverse *B
= 
Yes I’m going back to the sun yet I have a couple questions and I’m not gonna be able I do that but I’m sorry I don’t have a lot to say about to do this but I’m not going back to the sun today or
13.5 freshman well rounded off to 14 freshman
Wait I don’t really get it but if you mean the result it is -5x^2 + 5 tho
She spent $9.
$16+$6 is $22, so the total $31 minus $22 leaves us with the $9 she spent for the taxi.