Respostas

2014-05-12T14:14:59-03:00
(2x+1)(3x-1)
=2(3x-2)+3(2x+1)
= 6x-4+6x+3
=12x-1
.......................................
t/t^2+2
= [1(t^2+2)-2t(t)]/(t^2+2)^2
=(t^2+2-2t^2)/(t^2+2)^2
=-t^2+2/(t^2+2)^2
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