First, we have to isolate the t, or keep it by itself, to solve. To do that, we need to move everything with t in it to on side.
-5 - 2t + 2t = 3t + 2t
The -2t and + 2t cross out, leaving us with t on one side, which is exactly what we want!
-5 = 5t
But t isn't alone yet. We need to get rid of its five. To do that, we need to use the same process: use the opposite symbol. In 5t, 5 is being multiplied by t. To get rid of, we need to divide 5. BUT the mega rule in algebra... what you do to one side you must do to the other, or else the equation would not be true anymore, so...
-5/5 = 5t/5
-1 = t
There's your answer! Hope this helps!