Which example correctly demonstrates polynomial addition?(1 point)

To demonstrate polynomial addition, we need to combine the like terms from both polynomials correctly. Let's add the given polynomials step by step.

The two polynomials we are adding are:
1. \( 2x^2 + 6x + 1 \)
2. \( 3x^2 + 3x + 9 \)

Now, adding the like terms:
- For \(x^2\) terms: \(2x^2 + 3x^2 = 5x^2\)
- For \(x\) terms: \(6x + 3x = 9x\)
- For the constant terms: \(1 + 9 = 10\)

So, the sum is:
\[
(2x^2 + 6x + 1) + (3x^2 + 3x + 9) = 5x^2 + 9x + 10
\]

Thus, the correct answer that demonstrates polynomial addition is:
\[
(2x^2 + 6x + 1) + (3x^2 + 3x + 9) = 5x^2 + 9x + 10
\]

So the correct option is:
**(2x^2+6x+1)+(3x^2+3x+9)=5x^2+9x+10**.