published on: 2013-10-24 18:54:03
ccoleciona-dor.tumblr.com/post/64942798454/
ccoleciona-dor.tumblr.com/post/64972921246/
ccoleciona-dor.tumblr.com/post/64972940116/
ccoleciona-dor.tumblr.com/post/64973000517/
ccoleciona-dor.tumblr.com/post/64973231891/
▲= b² - 4.a.c