If 5 More Than 3 Times A Certain Number Is 10 Less Than 8 Times The Number, What Is The Number?

5 + 3n = -10 + 8n 15 = 5n    (add 10-3n to both sides) 3 = n

The number is 3.

Check  5 + 3*3 = -10 + 8*3  5 + 9 = -10 + 24  14 = 14    (yes)