Answer:
We just add numerators and rewrite denominator.
Adding unlike dominators:
We need to find the same denominators. You need to find the least common multiple (LCM) of the two denominators.
Step-by-step explanation:
You mean unlike denominators and like denominators.
Adding like dominators: We just add numerators and rewrite denominator :
Example : 
Adding unlike dominators:
We need to find the same denominators. You need to find the least common multiple (LCM) of the two denominators.
For example :

LCM for 5 and 4 is 20 : Now, divide by 5 and multiply by 1 for first fraction. 20 divide by 4 and multiply by 3 :

4.19004 x 10^5
sry I have to write extra stuff to send the answers :)
Answer:
Exponential
Step-by-step explanation:
Since the x is to the power of 4, a small increase in x is amplified when it becomes the output of y.
Edit: Here is a screenshot of the graph
The answer to ( 1+7 )•3/6 is 4 and (7•3)•2/6 is 7