Which shows 2/3 and 3/4 written as a pair of fractions with a common denominator ? 2/3 and 4/3 or 6/9 and 6/8 or 2/12 and 3/12 or 8/12 and 9/12

You have 2/3 and 3/4
You need to find common denominator
You need to multiply both bottoms to get the same number on the bottom
Shorter story you need to multiply the bottom numbers by a number to get the same number on the bottom
When you get that make sure you multiply both tops by the same number
2/3 3/4

3x4= 12. 4x3=12.
Your denominator is 12
Now multiply the numerator by the same number you multiplied the denominator by.
2x4=8. 3x3=9
Answers
8/12 and 9/12

8/12 and 9/12 shows them written both with a common denominator. When you find common denominators, you have to do the same to the numerator and denominator. The other answers have not done this. So we know it will not be the first choice because 3/4 cannot become a greater number by multiplying both the numerator and denominator by the same number. We know it won't be the second option because 3 isn't a factor of 8. It won't be the third option either because 3 is not a multiple of 2. So we are left with the last one.