So,
We're going to evaluate each expression as follows:
Let's begin with a:
[tex]\begin{gathered} 2(5+(3)(2)+4) \\ 2(5+6+4) \\ 2(15) \\ =30 \end{gathered}[/tex]Now, b:
[tex]\begin{gathered} 2((5+3)(2+4)) \\ 2((8)(6)) \\ =2(48) \\ =96 \end{gathered}[/tex]And, finally, c:
[tex]\begin{gathered} 2(5+3(2+4)) \\ 2(5+3(6)) \\ 2(5+18) \\ 2(23) \\ =46 \end{gathered}[/tex]Notice that if the parentheses change, the results wouldn't be the same.