\(\frac{\left(2t+1\right)^2}{4}+\frac{\left(1-t\right)3t}{3}< \frac{5t}{4}+1\)
\(\Leftrightarrow3\left(2t+1\right)\left(2t+1\right)+12t\left(1-t\right)< 15t+12\)
\(\Leftrightarrow12t^2+12t+3+12t-12t^2< 15t+12\)
\(\Leftrightarrow9t< 9\)
\(\Leftrightarrow t< 1\)
Vậy : ..............