1. The height (in meters) of a shot cannonball follows a trajectory given by $h(t) = -4.9t^2 + 14t - 0.4$ at time $t$ (in seconds). For how many seconds is the height of the cannonball at least $6$ meters?
2. What is the smallest distance between the origin and a point on the graph of $y=\dfrac{1}{\sqrt{2}}\left(x^2-3\right)$?
3. What is the maximum value of $4(x + 7)(2 - x)$, over all real numbers $x$?
thank you
1 solve 6 = -4.9t^2+14t-0.4 using quadratic equation a = -4.9 b = 14 c = - 6.4
you will get two values of t the time above 6 is between these times
3 Max will occur at the point between the two zeroes -7 and 2 middle is - 2.5
use this value for x in the equation to find the max value of the equation
