The answer you're looking for is, x = 3,-5
I'd do 9x4=36 because the 9 is from your money and the 4 is from your books. Now since you want to find out how much 4 books cost you just multiply that by 9
Step-by-step explanation:
-16 + 3n = - 8 - 5n
Bringing like terms on one side
3n + 5n = - 8 + 16
8n = 8
n = 8/8
N = 1