I search up name this what i found im not a girl

Based on what i know about mean, this doesn't add up.

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)}

Asquare parking lot has 6,400 square meters what is the length in meters