OK. 2 = -t² + 4t + 5
Subtract 2 from each side: 0 = -t² + 4t + 3
Multiply the right side by -1 : 0 = t² - 4t - 3
Unfortunately, this can't be factored. The only other way I know
to find the solutions to a quadratic equation is with the use of the
quadratic formula. When you do that, you get these solutions:
t = 2 + √7 = about 4.65
and
t = 2 - √7 = about -0.65 .
If this equation comes from a problem that involves real people throwing
real things into the air and making vertical motion, then you want only the
positive solution.
