Bonjour,
A=-9+(-4-7+6)+(-5+9-12)
A = - 9 + (- 11 + 6) + (- 17 + 9)
A = - 9 + (- 5) + (- 8)
A = - 9 - 5 - 8
A = - 22
B=3-6×2-(12-4+7)
B = 3 - 12 - (19 - 4)
B = 3 - 12 - 15
B = 3 - 27
B = - 24
C=5-3×4-2+10
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3+8×2-17
C = 5 - 12 - 2 + 10
3 + 16 - 17
C = 15 - 14
19 - 17
C = 1/2