(x²+x+1)+(x²-x+1)

To add the polynomials (x²+x+1) and (x²-x+1), we can combine like terms:

x² + x + 1 + x² - x + 1

Combining the like terms, we get:

(1x² + 1x²) + (1x - 1x) + (1 + 1)

Simplifying further:

2x² + 0x + 2

Therefore, the sum of (x²+x+1) and (x²-x+1) is 2x² + 2.