Hey there!
[tex]y = 3x+6 \\ \\ x = 2y \\ \\ \\ y = 3(2y) + 6 [/tex]
You would have to simplify both of your sides
We add [tex]6y [/tex] to the [tex]6 [/tex]
Like: [tex] y = 6y + 6 [/tex]
Now subtract [tex]6y [/tex] to your sides
Like: [tex]y - 6y \\ 6y + 6 - 6y = -5y = 6 [/tex]
Now we have to divide by [tex]-5[/tex] on each of your sides
Like: [tex] \frac{-5y}{-5} = \frac{-6}{5} [/tex]
Answer: [tex]y = \frac{-6}{5} [/tex]
Good luck on your assignment and enjoy your day!
~[tex]LoveYourselfFirst:)[/tex]