Respuesta :

Completing the square:
Divide the middle term by 2, and square the number.

x² + 11x + (11/2)² - (11/2)² = 3
x² + 11x + (11/2)² = 3 + (11/2)²
x² + 11x + 121/4 = 3 +121/4
x² + 11x + 121/4 = 133/4