i do not understand how to find the answer to the equation above

When you have the same variable on both sides of the equation you want to start by isolating the variable (in this case x) on one side.

I would start by adding 12 to each side

3x-12+12=-2x+83+12

-12+12 cancels out to zero and you add 12 to 83

This leaves you with 3x=-2x+95

Next add 2x to each side

3x+2x=-2x+2x+95

-2x+2x cancels out to zero

This leaves you with 5x=95

Now divide each side by 5

5x/5=95/5

5/5=1 which leaves you with 1x or just x if you prefer. 95/5=19

Therefore you answer is x=19

Hope this helps.