Let the two digits be represented by a and b.
a x b = 12 then, b = 12/a.
a + b = 13.........after substituting for b this becomes :-
a + 12/a = 13.....multiply throughout by a :-
a2 + 12 = 13a....re-arrange :-
a2 - 13a + 12 = 0
This factors as (a - 12)(a - 1) = 0
When a - 12 = 0 then a = 12
When a - 1 = 0 then a =1
As we have already substituted for b then b can take one of theses values and the two numbers are 1 and 12.
Note : The solution can be easily determined from the values supplied in the question but the process of finding the answer will apply to any such problem.
10 1
10
They are 13.
The numbers are: 16 and -3
The sum, meaning you add them together. 7+5=13.
The anwer is 8 and 5 and thedifference of the two is 3
10 and 3
1 and 12
The sum of the squares of the digits of 13 is 12 + 32 = 10. The sum of the squares of the digits of this result is 12 + 02 = 1. Because this process results in a 1, this number is a happy number.
13 and 22
9 x 3 = 27 9 + 3 = 12
Start with the smallest multiple of 13 and continue with the next smallest until finding one that fits the specifications. 13, sum of digits is 1 + 3 = 4 which is not prime 26, sum of digits is 2 + 6 = 8 which is not prime 39, sum of digits is 3 + 9 = 12 which is not prime 52, sum of digits is 5 + 2 = 7 which is prime So, 52 is the smallest positive multiple of 13 for which the sum of its digits is prime.
13 and 22
2145
12 and 13.
If the sum of 2 numbers is 25 and their product is 156, the numbers are 12 and 13.
13
13
If the sum of 2 numbers is 25 and their product is 156, the 2 numbers would be 12 and 13.