hello
the question here is
[tex]3\sqrt[]{7}(14-4\sqrt[]{56})[/tex]step 1
multiply through the bracket by the coeffiecient
[tex]\begin{gathered} 3\sqrt[]{7}(14-4\sqrt[]{56}) \\ (3\sqrt[]{7}\times14)-(3\sqrt[]{7}\times4\sqrt[]{56}) \\ (14\times3\sqrt[]{7})-3\sqrt[]{7}\times4\sqrt[]{4\times14} \\ (42\sqrt[]{7})-3\sqrt[]{7}\times8\sqrt[]{14} \\ (42\sqrt[]{7})-\lbrack(3\times8)\sqrt[]{7\times14} \\ 42\sqrt[]{7}-24\sqrt[]{98} \end{gathered}[/tex][tex]\begin{gathered} 42\sqrt[]{7}-24\sqrt[]{49\times2} \\ 42\sqrt[]{7}-24\times7\sqrt[]{2} \\ 42\sqrt[]{7}-168\sqrt[]{2} \end{gathered}[/tex]