Respostas

2013-08-06T13:26:36-03:00
12-(x-6).(x+1)=-12.(x²-11)
12-x²+1x-6x-6=-12x²+232
x²+12x²+1x-6x=232-12+6
13x²-5x=226
13x²-5x-226=0

E ai usa a formula de bhaskara.