20 points + brainliest = 30 points!

Answer:
see below
Step-by-step explanation:
Addition and subtraction are both closed under polynomials.
That means that when we add and subtract polynomials, we will end up with a polynomial
f(x) + g(x) will = always be a polynomial when we start with polynomials
f(x) - g(x) will = always be a polynomial when we start with polynomials
Answer:
[tex]\boxed{\mathrm{view \: explanation}}[/tex]
Step-by-step explanation:
A polynomial is an expression consisting of variables and coefficients.
[tex]f(x)[/tex] and [tex]g(x)[/tex] are polynomial functions.
Adding polynomials and subtracting polynomials is essentially combining like terms of polynomial expressions.
[tex]f(x)+g(x)[/tex] is always a polynomial
[tex]f(x)-g(x)[/tex] is always a polynomial
If you add, subtract or multiply any two polynomials then the result will be always a polynomial.