Kevin and his little sister, Katy, are trying to solve the system of equations shown below. Kevin thinks the new equation should be $3(6x-1)+2y=43$, while Katy thinks it should be $3x+2(6x-1)=43$. Who is correct and why?

$\begin{array}{l} y = 6x - 1 \\ 3x + 2y = 43 \end{array}$