Answer:
3x + 12
Explanation:
I got this answer because since 8x and -5x are like terms, you are able to subtract them from each other. 8x-5x is 3x. Since you cant add 12 to 5x because they aren't like terms, you leave the expression as it is right now. Finally, your answer is 3x + 12.
Hope I helped! Have a good day.