The polynomial remainder theorem states that the remainder upon dividing a polynomial

by

is the same as the value of

, so to find

you need to find the remainder upon dividing

You have
..... | 2 ... 14 ... -58
-10 | ... -20 ... 60
--------------------------
..... | 2 ... -6 .... 2
So the quotient and remainder upon dividing is

with a remainder of 2, which means

.
It went from 10 to -2, so you need to find the difference. The way you'd do this is: 10 - (-2). Do you know how to subtract a negative number from a positive number?
This doesn't represent an function. Because the output is uneven to the other outputs,
1=4, 2=7 if you divided 2 into 2 parts it would equal 1=3.5 not 4.
Answer:
To find the sum of interior angles in a polygon, we can use the formula:
where n is the number of sides.
Since this is pentagon (5 sides), then 
The missing angle would then be

Since angles on a straight line add up to 180, then


One weights 30lbs the other weights 54lbs