bonjour, a. (x +4)² b.(x+5)² c.(1+3x)(1-3x) d.(5+2x)(-2x+5)​

Réponse :

Bonjour,

a) (x + 4)² ⇔ (a + b)²

= x² + 2 × x × 4 + 4²

= x² + 8x + 16 ⇔ a² + 2ab + b²

b) (x + 5)² ⇔ (a + b)²

= x² + 2 × x × 5 + 5²

= x² + 10x + 25 ⇔ a² + 2ab + b²

c) (1 + 3x)(1 – 3x) ⇔ (a + b)(a – b)

= 1² – (3x)²

= 1 – 9x² ⇔ a² – b²

d) (5 + 2x)(–2x + 5)

= (5 + 2x)(5 – 2x) ⇔ (a + b)(a – b)

= 5² – (2x)²

= 25 – 4x² ⇔ a² – b²