Answer:
8 5/7
Step-by-step explanation:
278/7 = 39 5/7
39 5/7 - 31 = 8 5/7
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
= 
Answer:
Al final, Eduardo tenía 20 dulces.
Step-by-step explanation:
Dado que al principio Eduardo y Adrián tenían el mismo número de dulces, y Eduardo le dio a Adrián la mitad de los dulces que tenía, y después, Adrián le dio a Eduardo la mitad de los dulces que tenía él en ese momento, así que a Adrián le quedaron 12 dulces, para determinar cuántos dulces tenía Eduardo al final se debe realizar el siguiente cálculo:
Eduardo 1X = Adrián 1X
Eduardo 0.5X = Adrián 1.5X
Eduardo 1.25X = Adrián 0.75X
0.75 X = 12
X = 12 / 0.75
X = 16
1.25 X = 16 x 1.25 = 20
Así, al final, Eduardo tenía 20 dulces.
Answer:
x = -9, -3
Step-by-step explanation:
x^2 + 12x + 27 = 0
We need 2 numbers whose product is + 27 and whose sum is + 12. These are 3 and 9. So the factors are:-
(x + 3)(x + 9) and this = 0
So (x + 3) = 0 or x + 9 = 0
x = -3 , -9
