dado a equação s=20+3t determine: posição no instante 6so instante que passa pela posição 44m

 simples

S = 20 + 3t

t=6s

S = 20 + 3x6 =>  S= 20 + 18 => S = 38m

S=44m

44= 20 + 3t  =>  3t = 44-20  =>  3t = 24 => t = 24/3  => t = 8s

ok.

e fui.

Basta apenas substituir na equação T= 6s então S= 20+3(6)

                                                                                                S=38 m/s

                                                                          S=44 então   44=20+3t

                                                                                                  44-20=3t

                                                                                                  24/3=t

                                                                                                   t=8 s