You first want to leave your x and your number alone so you have to get rid of the 4. Easiest way to do it is add a 4 to the other side of the equation so it is now -10+4=2x or -6=2x. You now want to leave the x alone so you have to divide by 2 the -6 (-6/2=2x/2) That should be equal to -3 which is your answer. Remember, one is negative and since your signs are different your answer HAS to be negative!