Bonsoir,
1)
4x² +12x +9 -16 =
4x² +12x -7
2)
identité remarquable
(a-b) (a+b) = a² -b²
=> (2x+3 -16) (2x+3+16)= (2x -13)( 2x+ 19)
3)
x= 2
16 + 24 -7 = 33
x= 1/2
4* 1/4 +12* 1/2 -7=
4/4 +24/2 -7 =
1 +12 -7 = 6
4)
(2x+7) (2x-1) =0
soit
2x+7 = 0
2x=-7
x= -7/2
ou
2x-1= 0
2x= 1
