Answer :
[tex]8(3a+6)=9(2a-4)\ \ \ \ | omiting\ the\ bracket\\\\
24a+48=18a-36\ \ \ \ | subtract\ 18a\\\\
6a+48=-36\ \ \ \ | subtract\ 48\\\\
6a=-84\ \ \ \ | divide\ by\ 6\\\\
a=-14[/tex]
Expand the brackets so you get
24a+48=18a-36
then you take the smaller value of a from both sides which in this case is 18a
so then you are left with
6a+48=-36
then to get 6a on its own, you take away 48 from both sides
6a=-84
then you divide both sides by 6 to get the value of a
a=-14
24a+48=18a-36
then you take the smaller value of a from both sides which in this case is 18a
so then you are left with
6a+48=-36
then to get 6a on its own, you take away 48 from both sides
6a=-84
then you divide both sides by 6 to get the value of a
a=-14