bonjour
A = ( 12 x - 3 ) ( x + 5 ) - ( x - 6 ) ( 8 - 3 x )
= 12 x² + 60 x - 3 x - 15 - ( 8 x - 3 x² - 18 + 18 x )
= 12 x² + 57 x - 15 - 8 x + 3 x² + 18 - 18 x
= 15 x² + 31 x + 3
B = ( x + 3 )² - 2 ( x - 2 )²
= x² + 6 x + 9 - 2 ( x² - 4 x + 4 )
= x² + 6 x + 9 - 2 x² + 8 x - 8
= - x² + 14 x + 1
