Answer:
Gabriela Mistral works as a humanitarian for
days.
Step-by-step explanation:
Gabriela Mistral was a poet, diplomat, teacher and humanitarian such that each week she worked a certain amount of days as a poet diplomat teacher and humanitarian.
Ratio is 
Let
denotes total number of days Gabriela Mistral work.
As she works 12 days as a teacher,

Total number of days 
So,
she works as a humanitarian for
days.
Answer:
The three values are: 9, 10 and 11
To solve this equation (correct me if i'm wrong), you could first multiply the bottom equation by 3, to get 15y. After that, we get -4x-15y=-17 and -3x + 15y=-39, and if we add the 2 equations up, on top of each other, we get -7x=-56, and we can conclude that x=8, and with substitution (-32 - 15y = -17), we know that y=(-1)
Here's what I mean by on-top
-4x-15y=-17
-3x + 15y=-39
-7x=-56
Answer: y/3x
Step-by-step explanation: 3 times x is 3x, so y/3x