bonjour
a) 4 x² + 4 = 4 ( x² + 1)
b) 8 - 2 a = 2 ( 4 - a )
c) 5 xy - 10 x = 5 x ( y - 2 )
A = - 7 x + 14
B = 4 x² + 12 x + 5 x + 15 = 4 x² + 17 x + 15
C = 27 x - 9 + 3 x² - x = 3 x² + 26 x - 9
D = 30 x² - 18 x - 10 x + 6 = 30 x² - 28 x + 6
B - C = 4 x² + 17 x + 15 - ( 3 x² + 26 x - 9)
= 4 x² + 17 x + 15 - 3 x² - 26 x + 9
= x² - 9 x + 24
je te laisse faire le dernier