Answer:
[tex]y=\frac{a}{(9+3x)}[/tex]
Step-by-step explanation:
we have
[tex]A=9y+3yx[/tex]
Solve for y
That means -----> isolate the variable y
Step 1
Factor the variable y in the right side
[tex]a=y(9+3x)[/tex]
Step 2
Divide by [tex](9+3x)[/tex] both sides
[tex]a/(9+3x)=y(9+3x)/(9+3x)[/tex]
Step 3
Simplify
[tex]y=\frac{a}{(9+3x)}[/tex]