You can put this solution on YOUR website! the 3 and the 11 stay put.
you have
move the 29 (the smaller) to the bottom subtracting 29 and leaving y^10 in the denominator. . This is a positive exponent, as opposed to the equivalent (3/11)y^(-10)
the parentheses need to be there to insure that 3y^29 is in the numerator and 11y^39 is in the denominator.
without the parentheses, 3y^29/11y^39 would be equal to 3y^29/11 * y^39 which gives you a different result.
the problem appears to be in the denominator.
without the parentheses, you are dividing by 11 and then multiplying by y^39.
with the parentheses, you are dividing by 11 * y^39.
bottom line:
parentheses ensure you are processing what you think you are processing with no nasty surprises at the end because of the order of mathematical processing logic.
(3y^29)/(11y^39) is equivalent to 3/11 * y^29/y^39
which is equivalent to 3/11 * y^(29-39)
which is equivalent to 3/11 * y^(-10)
which is equivalent to 3/11 * 1/y^10)
which is equivalent to 3/(11 * y^10)
which is equivalent to 3/(11y^10)
that should be your answer.
the laws of exponents tell you that x^-y is equal to 1/x^y
that's how you convert that minus exponent to a positive exponent.