SVPPP AIDEZ MOI : Développer en utilisant la 1ere identité remarquable A = (x + 9)² B = (5x + 6)² C = (5x + 1)² + (-3x + 4)²

Réponse:

A = (x+9) (x+9)

= x^2 + 9x + 9x + 81

B = (5x+6) (5x+6)

5x * 5x = 25x^2

5x * 6 = 30x

6 * 5x = 30x

6 * 6 = 36

B = 25x^2 + 60 x + 36

C = [ (5x + 1) (5x + 1) ] + [ (-3x + 4) (-3x + 4) ]

5x * 5x = 25x^2 -3x * -3x = +9x^2

5x * 1 = 5x -3x * 4 = -12x

1 * 5x = 5x 4 * -3x = -12x

1 * 1 = 1 4 * 4 = 16

C = 25x^2 + 10x + 1 + (+9x^2) + (-24x) + 16

= 34x^2 + (-14x) + 17

= 34x^2 -14x + 17

Voilaa