Bao you is completeing the square to solve equation x^2-x-3=0 what should her first step be?

Idon’t understand this.. will someone ? will mark brainliest along with 20 points.

Aball is thrown from a height of 139 feet with an initial downward velocity of 15 ft/s. the ball's height h (in feet) after t seconds is given by the following. h=139-15t-16t^2 how long after the ball is thrown does it hit the ground? round your answer(s) to the nearest hundredth. (if there is more than one answer, use the "or" button.) t =

What is the value of x in the this question ?