Réponses

2013-11-12T16:45:52+01:00
(1-4x)(1+4x)
1+4x-4x-1
=0

(4x-5y)(4x+5y)
16x²+20xy-20xy-25y²
16x²-25y²

(a+b)(a-b)
a²-ab+ab-b²
a²-b²