Which Equation represents a line which is parallel to the line x-7y=-21?

Solve the system of equations. y= 2x y= x^2 - 15

The rumpart family is building a new room onto their house. the width of the new room will be 16 feet. the length of the room will be 4% greater than the width. write an expression to find the length of the new room. what will be the area of this new room?

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 =