Bonjour
A = 10(3x+5)² – 2 ( 6x - 3)2
A = 10(9x^2 + 30x + 25) - 2(36x^2 - 36x + 9)
A = 90x^2 + 300x + 250 - 72x^2 + 72x - 18
A = 18x^2 + 372x + 232
B = - 3(2x - 5) + 7 ( 3x - 2) (2- 6x)
B = -6x + 15 + 7(6x - 18x^2 - 4 + 12x)
B = -6x + 15 + 42x - 126x^2 - 28 + 84x
B = -126x^2 + 120x - 13
C = 8 ( 6x - 3) ( 6x + 3) - 9x ( 10x - 5)
C = 8(36x^2 - 9) - 90x^2 + 45x
C = 288x^2 - 72 - 90x^2 + 45x
C = 198x^2 + 45x - 72
D = - 2 ( 4- 7x)(4 + 7x) + 5 ( 3x + 7)2
D = -2(16 - 49x^2) + 5(9x^2 + 42x + 49)
D = -32 + 98x^2 + 45x^2 + 210x + 245
D = 143x^2 + 210x + 213
