Respostas

2013-07-07T21:18:14-03:00
80=130+15*t+1/2*10*t^2
15t+5t^2=50
5t^2+15t-50=0
simplificando..
t^2+3t-10=0
delta = 3^2-4*1*(-10)
delta= 49
X'= 5s e X''= -2s
RESPOTA; 2s
6 4 6