Find the value of t, if the value of 3x² + 5x – 2t equals to 8, when x = -1. 

Given, x = -1

3x² + 5x – 2t = 8
$\Rightarrow$ 3(-1)² + 5(-1) – 2t = 8
$\Rightarrow$3(1) – 5 – 2t = 8
$\Rightarrow$ 3 – 5 – 2t = 8
$\Rightarrow$ -2 – 2t = 8
$\Rightarrow$ -2t = 8 + 2
$\Rightarrow$-2t = 10
$\Rightarrow$t = -5
$\therefore$ the required value of t = -5.