Respostas

2013-09-06T11:43:30-03:00
(a-2b ) [a(b-31+b(1-a))]

=(a-2b ) [a(b-31+b-ab)]
=(a-2b ) [ab-31a+ab-a²b]
=a²b-31a²+a²b-a³b-2ab²+61ab-2ab²+2a²b²
=2a²b-31a²-a³b-4ab²+62ab+2a²b²