How can I understand it?

Question

Please help me to understand it.

function func(x) {
return(x+1)+x*3;
}
var y = func(2);
var z = func(y);
document.write(z);
And=37

Answer 1

ok first
func(2)
return(2+1)+2*3; => 3+6 => func(2)=9 => y=9
second
func(y) mean func(9)
return(9+1)+9*3; => 10+27 =>37

z = 37
hope you get it ;)

Answer 2

This code performs the following operation
func(2) = (2+1)+2*3=9
func(y) = func(9)= (9+1)+9*3=37
z=func(y)=37

Answer 3

thanks