algebra 1
posted by Lily .
This problem has a fraction in it.
Solve: square root of y =(numerator) 5+square root of 2. (Denominator)2
25.5+5square root of 2?

Is this your equation?
y = (5 + √2)/2
Anything divided by 2 would only be half as large. 
The y itself has a square root around it. 5+ square root of 2 is divided by 2.

P.S. There aren't any brackets.

There may not be any brackets explicitly, but whenever there is a numerator, there are implicit brackets around it. The same goes for the denominator.
For example,
Solve: square root of y =(numerator) 5+square root of 2. (Denominator)2
would translate to
√y = (5+√2) / 2
If we omit the brackets, it would become
√y = 5+√2 / 2
which means
√y = 5 + (√2 / 2)
by virtue of the rules of priority of multiplication over addition.
Additional parentheses must be inserted around numerators and denominators in fractions.
Back to your question, assuming the following equation is what you have:
√y = (5+√2) / 2
You can square both sides to give:
y = ±(5+√2)² / 4
=±(25+10√2 + 2)/4
=±(27+10√2)/4 
Thanks!