(1) The product $(3-\sqrt{5})(4+2\sqrt{5})$ can be expressed in the form $a+b\sqrt{5}$, where a and b are integers. Find a+b.
(2)What is the sum of all possible values of x such that $2x(x-10)=-50$?
(3) The equation $y = -4.9t^2 + 23.8t$ describes the height (in meters) of a projectile launched from the ground at 23.8 meters per second. In how many seconds will the projectile first reach 28 meters in height?
Thanks!
