Need help on this question

1. what is the phythaforean theorem? 2.what do we use it for? 1.what is the distance formula ? 2.what do we use it for?

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)}

What is the value of x in the equation (2)3) (x+6)= -18 a. -36 b. -33 c. -24 d. -18