please help on this one?

Answer: [tex]\bold{A.\quad x=\dfrac{C-By}{A}}[/tex]
Step-by-step explanation:
[tex]Ax + By = C\\\\Ax = C - By\quad \rightarrow \quad \text{(subtracted "By" from both sides)}\\\\x=\dfrac{C-By}{A}\quad \rightarrow \quad \text{(divided both sides by "A")}[/tex]