X+(5+6)=15

To solve the equation \( X + (5 + 6) = 15 \), first simplify the expression inside the parentheses:

\[ 5 + 6 = 11 \]

Substituting this back into the original equation gives:

\[ X + 11 = 15 \]

Next, isolate \( X \) by subtracting 11 from both sides of the equation:

\[ X = 15 - 11 \]

So,

\[ X = 4 \]

Thus, the solution is \( X = 4 \).