Verified Answer :

TSO

PEMDAS

P - PARENTHESIS
E - EXPONENTS
M - MULTIPLICATION
D - DIVISION
A - ADDITION
S - SUBTRACTION

So we do that from left to right:

\([ 7+(15 -3)/6]\times 3\)

First we do parenthesis:

\([ 7+12/6]\times 3\)

Now we have to take care of the next parenthesis. Inside of it is addition and division happening. So we have to do the division first:

\([ 7+2]\times 3\)

Now we do the addition:

\(9\times 3\)

Now there is only one thing left: Multiplication

\(27\)

Your final answer is

\(\bf{\huge{\boxed{27}}}\)