(x²+x+1)+(x²-x+1)

To simplify the expression, let's combine like terms:

(x²+x+1) + (x²-x+1)

First, let's simplify the brackets separately:

x² + x + 1 + x² - x + 1

Next, we can add the like terms together:

x² + x² + x - x + 1 + 1

Combining like terms, we have:

2x² + 2

So, the simplified expression is 2x² + 2.