Answer :

mumsy
if you need to find the y, and the 
4(y-3)+9-3y=0, then
we use PEMDAS, parenthesis first
4y-12+9-3y=0
4y-3y-12+9=0 
y-3=0 add 3 on both sides
y=3
AyaZ
[tex]4(y-3)+9-3y=0 \\ 4y-12+9-3y=0 \\ y-3=0 \\ y=3[/tex]