Answer:
I believe it's the first one
Given:
The expression is:

It leaves the same remainder when divided by x -2 or by x+1.
To prove:

Solution:
Remainder theorem: If a polynomial P(x) is divided by (x-c), thent he remainder is P(c).
Let the given polynomial is:

It leaves the same remainder when divided by x -2 or by x+1. By using remainder theorem, we can say that
...(i)
Substituting
in the given polynomial.


Substituting
in the given polynomial.



Now, substitute the values of P(2) and P(-1) in (i), we get




Divide both sides by 3.


Hence proved.
Hello,
We know that if we make the same operation on both sides, we don't affect the equation:
For example:

Do you see? we add 2 on both sides and we don't affect the equality
We can do the same with the multiplication, for example
4=4 (i'll multiply both sides by 1/2)

Now, we do exactly the same in your excercise: