Final answer:
The line of symmetry of the equation y = x² + x + 1 is x = -1/2(option b).
Step-by-step explanation:
The line of symmetry of the equation y = x² + x + 1 is x = -1/2(option b).
To find the line of symmetry of a quadratic equation in the form y = ax² + bx + c, you can use the formula x = -b / (2a). In this equation, a = 1 and b = 1. Plugging these values into the formula gives:
x = -1 / (2 * 1) = -1/2
Therefore, the line of symmetry is x = -1/2.