The equation describes the height (in feet) of a projectile seconds after it is launched from the surface of Mars at feet per second. In how many seconds will the projectile first reach feet in height? Express your answer as a decimal rounded to the nearest tenth.

Guest Aug 27, 2022

#1**0 **

y=-6t^2+43t

In how many seconds will the projectile first reach 77 feet in height?

**Hello Guest!**

\(77=6t^2+43t\\ -6t^2+43t-77=0\ |\ /(-6)\\ t^2-\frac{43}{6}+\frac{77}{6}=0\\ t=\frac{43}{12}\pm \sqrt{(\frac{43}{12})^2-\frac{77}{6}}\\ \color{blue}t\in \{3.5,3.\overline 6\}\)

**In 3.5 seconds will the projectile first reach 77 feet in height.**

** !**

asinus Aug 28, 2022