Please answer this correctly

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

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.

Can someone me i’m confused. will give brainliest and a whole bunch of points