Bonjour,

Calculer les expressions

A = 2 × x + 1 + x + x

A = 2x + 1 + 2x

A = 4x + 1

B = 2 + x × x + 2

B = 2 + x^2 + 2

B = x^(2) + 4

a) Lorsque x = 1

A = 4 × 1 + 1 = 4 + 1

A = 5

B = 1^(2) + 4 = 1 + 4

B = 5

b) Lorsque x = 3

A = 4 × 3 + 1 = 12 + 1

A = 13

B = 3^(2) + 4 = 9 + 4

B = 13

c) Faux

Contre exemple : pour x < 0

prenons x = -2

• A = 4 × (-2) + 1 = -8 + 1 = -7

• B = (-2)^2 + 4 = 4 + 4 = 8

Bonne journée !

Réponse :

Bonjour

Explications étape par étape

Voici 2 expressions

A = 2 X x +1 +x +x  pour x = 3

2 X 3 + 1 + 3 +3 = 6 + 7 = 13

pour x = 1

2 X x +1 +x +x = 2 X 1 +1 + 1 + 1 = 2 + 3 = 5

B = 2 +x X x +2

pour x = 1

2 X 1 X 1 +2 = 2 + 2 = 4

pour x = 3

2 X 3 X 3 +2 = 20

2 X x +1 + x +x = 2 X x Xx Xx +2   vrai ou faux

2x +1 +2x = 2x³ +2  faux