2 Développer, réduire et ordonner ces expressions. a) 3x(x + 1) + (x-2)(3 - x) b) (3t - 5)2 c) (x + 10)(x - 10) - 100 d) 3(x + 5)2 Merci de votre aide

a) 3x(x+1) + (×-2)(3-x)

3x² +3x +3x -x² -6 +2x

2x² + 8x -6

b) (3t-5)²

9t² -2×3t×5 +25

9t² -30t +25

c) (x+10)(x-10) -100

x² -10x +10x -100 -100

x² -200

d) 3(x+5)²

3(x² +2×x×5 +25)

3(x² +10x +25)

3x² +30x +75

Bonjour,

a) 3x(x + 1) + (x-2)(3 - x)

= 3x² +3x + 3x -x² -6 +2x

=2x² +8x -6

b) (3t - 5)² =

IR (a-b)²

= 9t² -30t+25

c) (x + 10)(x - 10) - 100

IR (a-b) (a+b)

= x² -100 -100

= x² -200

d) 3(x + 5)²

IR (a+b)²

= 3* (x² +10x +25)  

= 3x² +30x +75