if someone could just show me how to do this, that would be grate!
** I know you cross multiply and divid, but what do you do after that? What do I do with the x+1 and 3x??

2/x+1 = 6/15


&


3x/12 = 3/12

2/x+1 = 6/15

(x + 1)/2 = 15/6

(x + 1)/2 = 5/2

X + 1 = 5

x = 5 - 1 = 4