CFAI march mock AM greensnacks qns 4

Can anyone enlighten me on how dividend yield comes into place here? Not too sure about how the answer is able to rearrange GGM model into g= (r-g) / (1+d). Many thanks!

its not g= (r-g) / (1+d)

its supposed to be Do/Po = (r-g)/(1+d)

Do/Po = dividend yield

See here: http://www.analystforum.com/forums/cfa-forums/cfa-level-ii-forum/91332696