Need to pass this semester so please help

Given: x + y = 6. if xe (-15, -6, -1), then which of the following sets of ordered pairs are solutions? © {(-15, -21), (-6, -12), (-1, -7)} [(-15, 21), (-6, , 7)} {(-15, 21), (-6, 12), (-1, -7)}

Use set builder notation to represent the following set: { -3, -2, -1, 0}

How do you solve a question like this?