Question 1083924


let r(x) = 2x^2


let s(x) = x^2


r(x) + s(x) = 2x^2 + x^2 = 3x^2


s(x) + r(x) = x^2 +2x^2 = 3x^2


they're the same


r(x) - s(x) = 2x^2 - x^2 = x^2


s(x) - r(x) = x^2 - 2x^2 = -x^2


they're different.


this is no different than the rules of arithmetic that state that addition is commutative but subtraction is not.