Répondre :
Bonjour,
A = 2012^2 - 2012 - 2011
A = 2012(2012 - 1) - 2011
A = 2012 x 2011 - 2011
A = 2011(2012 - 1)
A = 2011 x 2011
A = 2011^2
A = 2012^2 - 2012 - 2011
A = 2012(2012 - 1) - 2011
A = 2012 x 2011 - 2011
A = 2011(2012 - 1)
A = 2011 x 2011
A = 2011^2