1/a =6(6x-9) +4(3+5x) -6(11x-7)

a = 36x-54+12+20x-66x+42

a =36x+20x-66x-54+12+42

a = 56x-66x-54+54

a = -10x

a = -10(638.529

)a = - 6385.292

/b =(4x+1)²+(3x+2)(x-4)

b = 16x²+8x+1+3x²-12x+2x-8

b = 19x²-2x-7

c =(3x-1)(3x+1) -5x(-2x+3) +13x-6

c =9x²+3x-3x-1 +10x²-15x+13x-6

c = 19x²-2x-7

donc oui b=c

3/

x-6 = 16-6 = 10

(x-6)² = (16-6)² =10² = 100

x-4 = 16-4 =12

x-9 = 16-9 = 7

d=(x-6)²-(x-4)(x-9) = (16-6)² -(x-4)(x-9) = 100 -12x7 = 100-84 = 16

x-6 = 40-6 = 34

(x-6)² = 34² =1156

x-4 = 40-4 =36

x-9 =40-9 = 31

d = 1156 - 36x31 = 1156 -1116 =40

b) on constate que le resultat de D correpond au chiffre de depart soit x

c)

d=(x-6)²-(x-4)(x-9)

d = x²-12x+36-(x²-9x-4x+36)

d =x²-12x+36-x²+13x-36

d =x 

3294² -3296x3291

soit x = 3300

donc

3294 = x-6

3296 = x-4

3291 = x-9

(x-6)²-(x-4)(x-9)

= x

donc 33300

donc