#### Answer

$t=0$

#### Work Step by Step

We are given the equation $6(t+3)=-2+20$. In order to solve, we must first use the distributive property to simplify the left side.
$6(t+3)=6(t)+6(3)=6t+18=-2+20$
Next, we can combine like terms on the right side.
$6t+18=-2+20=18$
Subtract 18 from both sides.
$6t+18-18=18-18$
$6t=0$
Divide both sides by 6.
$\frac{6t}{6}=\frac{0}{6}$
Therefore, $t=0$.