To find the percentage of something you simply divide the amounts. 17 of the 24 books were mystery so to find the percentage of mystery books you do 17 divided by 24
3 | x+12 |=6 Start by distributing 3 to both x and 12 You get 3x+36=6 Subtract 36 from both sides You then get 3x=-30 Divide 3 from both sides getting x= -10