Respuesta :
The product of (x + 3)² demonstrates the closure property of multiplication. [tex]\rm x^{2} + 6x + 9[/tex] is a polynomial. Option D is correct.
What is polynomial?
Polynomial is an algebraic expression that consists of variables and coefficients. Variable are called unknown. We can apply arithmetic operations such as addition, subtraction, etc. But not divisible by variable.
What is the closure property of multiplication?
A set is closed under an operation when we do that operation on the member of the set and we always get a set member.
Given
An expression is (x + 3)²
On simplifying, we have
[tex]\rm (x + 3)(x + 3)\\\\x (x + 3) + 3 (x + 3)\\\\x^{2} +3x +3x +3^2\\\\x^{2} +6x + 9[/tex]
Thus, [tex]\rm x^{2} + 6x + 9[/tex] is a polynomial.
More about the polynomial link is given below.
https://brainly.com/question/17822016
