You divide the 15x by the 124. I know it sounds weird because you'll get a decimal, but that is what you are supposed to do because 124 is not a factor of 5.
Add 19 to both sides. -15x-19+19=124+19. Then, simplify which is -15x=143. Third, divide both sides with -15. so Then it will look like this= -15x/-15=143/-15. After that, you simplify which is - 143/15 so answer is - 143/15
