[tex]2\left(4-16\right)-\left(-30\right) \ \textgreater \ Follow\;PEMDAS \ \textgreater \ 4-16= -12 [/tex]
[tex]2\left(-12\right)-\left(-30\right) \ \textgreater \ \mathrm{Apply\:rule\:}a\cdot \left(-b\right)\:=\:-a\cdot \:b [/tex]
[tex]2\left(-12\right)=-2\cdot \:12=-24 \ \textgreater \ 24-\left(-30\right)[/tex]
[tex]\mathrm{Apply\:rule\:}-\left(-a\right)\:=\:+a \ \textgreater \ -\left(-30\right)=+30 \ \textgreater \ -24+30=6[/tex]
Therefore they did not apply the correct rule at the end giving the wrong answer.
Hope this helps!
