first, we have to apply distributive property to the parenthesis:
[tex]4+2\left[4n-7\left(n)-7(-1\right)\right]-6[/tex][tex]4+2\left[4n-7n+7\right]-6[/tex][tex]\text{.}[/tex][tex]4+2\left[-3n+7\right]-6[/tex]Next, solve the brackets:
[tex]4+2(-3n)+2(7)-6[/tex][tex]4-6n+14-6[/tex]Add alike terms:
[tex]12-6n[/tex]