Scientific notation is a system for expressing very large or very small numbers in a compact manner. It uses the idea that such numbers can be rewritten as a simple number multiplied by 10 raised to a certain exponent, or power.
The whole thing flips around and ends up being t = 3k/?
The answer is -5, -5 added by 5 cancels each other out. Then when you add 4x + 8x, you get 12x. So when you do 12x= -60, you get -5.