4(1sur2y-1)(1sur2y+1) merci de m aider urgent
4(1/2y-1)(1/2y/1)=4(1/4y²+2y-2y-1)=4(1/4y²-1)=4/4y²-1
4(1/2 y-1)(1/2 y+1 )
=(4^1/2 y ) -(4^1) (1/2 y+1)
=(2y -4 ) (1/2 y+1)
=2y^1/2 y +2y ^1 -4^1/2 y -4^1
=1y² +2y -2y -4
=1y²-4
