Does anyone know what this n does in the equation?

(x + 5 - 6).

The symbol ∩ signifies the intersection of the left operand and the right operand. Here, it means "and", as it often does.

Step-by-step explanation:

The solution to the left inequality is x < - 1.

The solution to the right inequality is x > - 3.

The intersection symbol (∩) means you are interested in the interval where these solutions overlap-the intersection of the solutions: - 3 < x < - 1; (-3, - 1) in interval notation.