Sorry if it's wrong, I tried
So 2x+12=5x-9
you want all of the unknowns on one side and all of the known values on the other or
subtract 2x from both sides
12=3x-9
add 9 to both sides
21=3x
divide both sides by 3
7=x
3: independent
4: dependent
9/3 =3
(X+7)^2/ (x+7) = x+7
1/x-1
3(x+7)/x-1
3x+21/x-1
Surely 7 aswell? Hope that helps
