Question 1118705
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h=-3(t-3)^2+18, where t is the time in seconds after the ball was hit. 
a) What was the maximum height reached by the baseball?
b) When did the baseball reach its maximum height?
c) At what time(s) was the baseball at the height of 10m?
d) Approximately when did the baseball hit the ground? 
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The form of the equation indicates the maximum height or vertex.
Maximum was 18 meters after 3 seconds.  (a).



(c)
Time when 10 meters high
{{{-3(t-3)^2+18=10}}}
{{{-3(t-3)^2=-8}}}
{{{(t-3)^2=8/3}}}
{{{t-3=0+- sqrt(8/3)}}}
{{{t=3+- sqrt(8/3)}}}
{{{t=3+- 1.633}}}
{{{t=1.37}}}  or  {{{t=4.63}}}