If 12 is added to the square of a positive integer, the result is 133. find the positive integer

1. Integers numbers are defined as the set of numbers that is formed by Positive numbers, which are also called "Natural numbers"; Negative numbers (They are less than zero) and zero (This has no sign). This set is represented with the letter "Z". Therefore: Z={...-2, -1, 0, 1, 2 ...}.
 
 2. So, if 12 is added to the square of a positive integer, you can write the following the expression: 
 12+x²=133
 
 3. You can obtain the value of the positive integer "x", by clearing it. Then, you have:
 
 12+x²=133
 x²=133-12
 x=√(133-12)
 x=√121
 x=11
 
 Therefore, the positive integer is: 11