### Instruction: What is the greatest common factor of 30, 90 and 75?### Response: To find the greatest common factor of three numbers, I need to find the largest positive integer that divides all three numbers evenly.
One way to do this is to factorize each number into prime factors and look for common factors.
30 = 2 x 3 x 5, 90 = 2 x 3 x 3 x 5, 75 = 3 x 5 x 5.