Help em với, 3h em phải nộp rồi

Ta có:

$2y = 6x$ `=>`$x = 3y$.

b)

\begin{array}{|c|c|c|}\hline \text{x}&\text{-12}&\text{-3}&\text{3}&\text{6}&\text{9}\\\hline \text{y = 3x}&\text{-4}&\text{-1}&\text{1}\text{}&\text{2}&\text{3}\\\hline\end{array}