Réponses

2014-01-13T18:08:32+01:00
(7x-4)(-3x+8)=(12+8*7)x
-21x²+56x+12x-32=(12+56)x
-21x²+68x-32=12x+56x
-21x²+68x-12x-56x=32
-21x²=32
-x²=32/21
x= + ou - racine de 32/21