Can someone please help me with this two questions I need to get it right.

What is the missing constant term in the perfect square that starts with x^2 -20x

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)}

1. a right triangle is graphed on a coordinate plane. find the length of the hypotenuse. round your answer to the nearest tenth. 2. use the angle relationship in the figure below to solve for the value of x. assume that lines a and b are parallel and line c is a transversal.