<PRE><B>Question 821983</B>
---
h(t) = -16t^2 + 130t + 7.5 = 30
-16t^2 + 130t - 22.5 = 0
---
the above quadratic equation is in standard form, with a=-16, b=130, and c=-22.5
---
to solve the quadratic equation, by using the quadratic formula, copy and paste this:
-16 130 -22.5
into this solver: https://sooeet.com/math/quadratic-equation-solver.php
---
the two real roots (i.e. the two x-intercepts), of the quadratic are:
t = 0.176929739
t = 7.94807026
---
answer:
the ball is at 30 ft and falling at time t=7.948 seconds.
---
Solve and graph linear equations:
https://sooeet.com/math/linear-equation-solver.php
---
Solve quadratic equations, quadratic formula:
https://sooeet.com/math/quadratic-formula-solver.php
---
Solve systems of linear equations up to 6-equations 6-variables:
https://sooeet.com/math/system-of-linear-equations-solver.php</PRE>