bonjour
A = x² + 6 x - x = x² + 5 x
B = 2 x - xy + 3 xy = 2 x + 2 x y
C = 3 x² + 12 x - x² = 2 x² + 12 x
D = 9 x ³ - 54 x + 2 x²
E = 15 x + 25 x² + 5 x + x² + 8 x² + 4 x
E = 34 x² + 24 x