+335 The equation $y = -6t^2 + 43t$ describes the height (in feet) of a projectile $t$ seconds after it is launched from the surface of Mars at 43 feet per second. In how many seconds will the projectile first reach 77 feet in height? Express your answer as a decimal rounded to the nearest tenth.
+37146 Just put in 77 for y ...then solve for 't ' using the Quadratic formula
77 = - 6t2 + 43t
-6t2 +43t -77 = 0
a = -6 b = 43 c = -77
\(t = {-b \pm \sqrt{b^2-4ac} \over 2a}\) throw out any negative 't' values
