Answer:
12
Step-by-step explanation:
see the pic for the steps
Find common variables. I wrote the ones I found above the polynomial. write them in parentheses the first number will have the variable. now it's just a matter of figuring out how to order it so that the first terms added to the second terms equal to the middle term of the polynomial. ... I think this is right. you could always look on wikiHow if I'm wrong.
Here is your answer

REASON:

: The opposite sides of a parallelogram are equal.
So, in above given figure

(measures of opposite sides)




HOPE IT IS USEFUL