(distribute)
(collect like-terms)
(we flipped the sign because we divided by a negative)

First you do 150 divided by 20, which equals 7.5, so then you would do 7.5 times 6 and that equals 45 minutes. Hope that helped!
X=45 since 90-45=45
Hope this helps
Remember the equation to find the circumference?
Equation of circumference: Pi x 2(radius)
Therefore, 3.141592654 x 2(6ft) = 37.7 feet
Check the pictures below.
if we knew the roots/solutions of the equation, we can set h(s) = 0 and solve for "s" to find out how many seconds is it when the height is 0.
if you notice in the first picture, when f(x) = 0, is when the parabola hits a root/solution or the ground, for David he'll be hitting the water surface, and the equation that has both of those roots/solutions conspicuous is
h(s) = -4.9(s - 2)(s + 1).