Sure, let's simplify the expression step by step. The expression we need to simplify is:
[tex]\[ 3(4 + 5) - 6 \][/tex]
1. Simplify the expression inside the parentheses:
[tex]\[ 4 + 5 = 9 \][/tex]
Now the expression becomes:
[tex]\[ 3 \times 9 - 6 \][/tex]
2. Multiply the result by 3:
[tex]\[ 3 \times 9 = 27 \][/tex]
Now the expression becomes:
[tex]\[ 27 - 6 \][/tex]
3. Subtract 6 from the result of the multiplication:
[tex]\[ 27 - 6 = 21 \][/tex]
So, the simplified result of the expression [tex]\( 3(4 + 5) - 6 \)[/tex] is [tex]\( 21 \)[/tex].
Therefore, the correct answer is:
[tex]\[ \boxed{21} \][/tex]
