Hey there!
The answer to your question is 
Given:

First, we can start by adding like terms. The following are like terms:



Now, we can add these pairs together, giving us:



Now, add all this together, and we get our answer as:

Have a terrificly amazing day!
So first find the factors of the denomenatores
14=2 times 7
7=7
21=7 times 3
common one would be having at least one 2, one 7, and one 3
find what numbers can be made by all of them
2 times 7 times 3
2 times 7
7
7 times 3
they are all in it
2 times 3 time s7=42
common denoomenator is 42
V = 8, because it can’t be simplified any further.
Answer:
x² + 10x + 25 = 31
Step-by-step explanation:
To complete the square use half the x coefficent (10/2 = 5)
and square it (5² = 25)
Then add it to both sides
x² + 10x + 25 = 6 + 25
x² + 10x + 25 = 31