9 * 0 + 1 = 1 9 * 1 + 2 = 11 9 * 2 + 3 = 21 what is the process of guessing the nth equation and the solution I don't know the rules,

9 * 0 + 1 = 1 9 * 1 + 2 = 11 9 * 2 + 3 = 21 what is the process of guessing the nth equation and the solution I don't know the rules,

9*(n-1)+n=10*(n-1)+1