Hello,
s=48t-16t²
a)
s=0==>16t(3-t)=0==>t=0 or t=3
b)
s>32==>48t-16t²>32===>16(t²-3t+2)<0
Δ=9-8=1
==>16(t-1)(t-2)<0
==>1<t<2 (negative between the roots)
s=48t-16t²
a)
s=0==>16t(3-t)=0==>t=0 or t=3
b)
s>32==>48t-16t²>32===>16(t²-3t+2)<0
Δ=9-8=1
==>16(t-1)(t-2)<0
==>1<t<2 (negative between the roots)