Yes your answer is correct... Because as per the question the equation formed should be y = 5(3)^x.
4k+mn=n-3
3(4k+mn)= 12k+mn
So, 12k+mn=n
2 because you do what is in parenthesis first :)
I would go for Obtuse from the 120° angle, Acute from the either the 20° and 40°, and scalene since all angles are unequal