Question 1117160
Your formula for height has a typo.
The height {{{(h)}}} (in feet) after {{{t}}} seconds can be calculated as
{{{h=-16*t^2+123*t}}} .
We can find the height after {{{t=5}}} seconds,
by just plugging in {{{5}}} for {{{t}}} in the correct formula:
{{{h=-16*5^2+123*5=-16*25+615=-400+615=215}}} .
Five seconds after the object is launched upwards,
its height is {{{highlight(215 feet)}}} .