Question 7169
{{{2a^2-6a^2-108a}}}.

Adding variables with same powers we get

{{{ (2a^2 - 6a^2) -108a}}}

{{{ -4a^2 -108a}}}

{{{a( 4a -108)=0}}}
Equating each expression to zero
{{{a=0}}}
and
{{{( 4a -108)=0}}}
we get
{{{ 4a = 108 }}}

{{{a = 108/4}}}
a=27 and a=0