Tommy is twice as old as his younger sister. the sum of the siblings' ages is 21. which equation can be used to determine the age of tommy's younger sister?

Can (3,5 and square root 34) be sides on a right triangle?

Consider 6x2 + 6x + 1. which term immediately tells you that this expression is not a perfect square trinomial? justify your answer

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 =