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2x² – 2x – 4 = 0
7
2x² – 2x – 4 = 0 a = b = c = 2 – 2 – 4 Calcul du discriminant : ac b 4 2 ) 4 ( 2 4 ) 2 ( 2 = 36 > 0, donc l’équation admet deux solutions 4 4 4 6 2 2 2 36 2 2 1 1 x a b x 4 8 4 6 2 2 2 36 2 2 2 2 x a b x x 1 = – 1 x 2 = 2
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2x² – 2x – 4 = 0. Calcul du discriminant :. a = b = c =. 2 – 2 – 4. D = 36. D > 0, donc l’équation admet deux solutions. x 2 = 2. x 1 = – 1. x² + 4x + 3 = 0. Calcul du discriminant :. a = b = c =. 1 4 3. D = 4. - PowerPoint PPT Presentation
Transcript of 2x² – 2x – 4 = 0
2x² – 2x – 4 = 0
a =
b =
c =
2
– 2
– 4
Calcul du discriminant :
acb 42 )4(24)2( 2
= 36
> 0, donc l’équation admet deux solutions
4
4
4
62
22
362
2
1
1
x
a
bx
4
8
4
62
22
362
2
2
2
x
a
bx
x1 = – 1 x2 = 2
x² + 4x + 3 = 0
a =
b =
c =
1
4
3
Calcul du discriminant :
acb 42 31442
= 4
> 0, donc l’équation admet deux solutions
2
6
2
24
12
44
2
1
1
x
a
bx
2
2
2
24
12
44
2
2
2
x
a
bx
x1 = – 3 x2 = – 1
6x² + 6x – 12 = 0
a =
b =
c =
6
6
–12
Calcul du discriminant :
acb 42 31442
= 324
> 0, donc l’équation admet deux solutions
12
24
12
186
62
3246
2
1
1
x
a
bx
12
12
12
186
62
3246
2
2
2
x
a
bx
x1 = – 2 x2 = 1
x² + 8x + 16 = 0
a =
b =
c =
1
8
16
Calcul du discriminant :
acb 42 161482
= 0
= 0, donc l’équation admet une solution
2
8
12
82
x
a
bx
x = – 4
x² – 6x + 7 = –2
a =
b =
c =
1
– 6
9
Calcul du discriminant :
acb 42 914)6( 2
= 0
= 0, donc l’équation admet une solution
2
6
12
62
x
a
bx
x = 3
x² – 6x + 9 = 0
différent de zéro !!!
– 2x² +3x – 4 = 0
a =
b =
c =
– 2
3
– 4
Calcul du discriminant :
acb 42 )4()2(432
= – 23
< 0, donc l’équation n’admet pas de solution
4x² – x + 1 = 0
a =
b =
c =
4
– 1
1
Calcul du discriminant :
acb 42 144)1( 2
= – 15
< 0, donc l’équation n’admet pas de solution
