Answer:
x = -14
Explanation:
First, you will add 10 to both sides, to get -3x=42, so basicallly you are just simplifying it. Then, you will divide both sides by -3, so you can get x by itself, which you would then be left with x=-14. A little extra information, when you divide a positive number by a negative number it will result in a negative number, hence how I got -14. I hope this helps :)