27 Calculer.
a. 3 x 5-(5-12)
b. 5-(3-5 × 6)
c. 4x (2-3 x 9) +7 d. 9x (-2-4 x 5) - 3
e. -63: (2-3 x 7+5 x 2) - 11
f. 48: (2-12:4-7)-4
28 Calcule