> Converting infix to prefix?

Converting infix to prefix?

Posted at: 2014-06-09 
Infix: (2 + (x * 12)) / ((1 / 3) + (7 / a)) Converted to prefix p: (/ (+ 2 (* x 12)) (+ (/ 1 3)(/ 7 a))) Is that the correct way to do it?
http://web.cecs.pdx.edu/~harry/compilers/slides/IntroPart2.pdf