Guys need urgent help

I'm new to this, I have a test tmrw and Idk how to use the y button on my casio fx991cw

Like for an example I need to do this ( not a real sum ) 2x+4x×3y÷9y

Idk how to do it, need help fast

I'm new to this, I have a test tmrw and Idk how to use the y button on my casio fx991cw

Like for an example I need to do this ( not a real sum ) 2x+4x×3y÷9y

Idk how to do it, need help fast