5/7:3/4=5/7*4/3=20/21 what was the error

5/7 ➗ 3/4

To divide the fractions you switch the numerator and denominator in the second fraction. By doing this you make the fractions multiply instead of divide.

So now the equation is

5/7 ✖️ 4/3

To get a common factor we will make the denominator of both of the fractions 21.

So now the equation is

15/21 ✖️ 28/21

To multiply fractions you multiply both numerators and both denominators.

So now the equation is

420/441

So to simplify the equation we divide the numerator and denominator by 21.

So now the equation is

20/21

So the question must be wrong or a trick question because the answer was correct.