Factor pairs of 105 are any two numbers that, when multiplied together, equal 105. The question to ask is “what two numbers multiplied together equal 105?” Every factor can be paired with another factor, and multiplying the two will result in 105.
To find the factor pairs of 105, follow these steps:
Step 1:
Find the smallest prime number that is larger than 1, and is a factor of 105. For reference, the first prime numbers to check are 2, 3, 5, 7, 11, and 13. In this case, the smallest factor that’s a prime number larger than 1 is 3.
Step 2:
Divide 105 by the smallest prime factor, in this case, 3:
105 ÷ 3 = 35
3 and 35 will make a new factor pair.
Step 3:
Repeat Steps 1 and 2, using 35 as the new focus. Find the smallest prime factor that isn’t 1, and divide 35 by that number. In this case, 5 is the new smallest prime factor:
35 ÷ 5 = 7
Remember that this new factor pair is only for the factors of 35, not 105. So, to finish the factor pair for 105, you’d multiply 3 and 5 before pairing with 7:
3 x 5 = 15
Step 4:
Repeat this process until there are no longer any prime factors larger than one to divide by. At the end, you should have the full list of factor pairs.
Here are all the factor pairs for 105:
(1, 105), (3, 35), (5, 21), (7, 15)
So, to list all the factors of 105: 1, 3, 5, 7, 15, 21, 35, 105
The negative factors of 105 would be: -1, -3, -5, -7, -15, -21, -35, -105