Answer:
3 gallons
Step-by-step explanation:
Let
x ----> the amount of pure acid (100% solution) in gallons
Remember that
we know that
solve for x
therefore
3 gallons of pure acid should be mixed with 3 gallons of a 20% acid solution in order to get a 60% acid solution
you can only see values of 
Ranging from $-3$ to $3$ and they're included, so domain is $[-3,3]$
and $y$ values ranging from $-2$ to $4$ but $-2$ is not included so range is $(-2,4]$
Answer:
the answer is 85° because all angles in a triangle add up to 180
so u add them both up, subtract from 180 n u get 85
