Now you want to solve for x by getting it by itself.
You can subtract the 8x from the right side (either 8x or 5x will work)
Now combine like terms.
Now, subtract the 5 to the other side of the equation.
Next, divide -3 into itself and the other side of the equation.
Now your answer:
x=7
Remember: positive X negative = negative
negative X negative = positive