Question 62234
The general idea is to get all references to the variable on one side and the numbers on the other.

{{{16.8 + 3.2t=-13.6t}}} Get all the t's on one side by subtracting 3.2t from each side
{{{16.8 + 3.2t - 3.2t=-13.6t - 3.2t}}}
{{{16.8 =-16.8t}}} Divide both sides by -16.8 to get t on its own.
{{{16.8/-16.8 =(-16.8t) / -16.8}}}
-1 = t

So the value of t which makes the equation correct is t = -1.