aidez moi svp c'st pour demain !!!

A = (1/4 - 1/5) x (7 + 37/9)
A = (5/20 - 4/20) x (63/9 + 37/9)
A = 1/20 x 100/9
A = 100/(20 * 9)
A = (5 * 20) / (20 * 9)
A = 5/9

B = (5 x 10^8 x 4) / (0,25 x (10^-2)^2)
B = (5 x 4 x 10^8) / (0,25 x 10^-4)
B = (5 x 4 x 10^8) / (1/4 x 10^-4)
B = (20 x 10^8 x 4 x 10^4)
B = 80 x 10^12

C = 4V6 - 5V54 + V150
C = 4V6 - 5V(6 * 9) + V(6 * 25)
C = 4V6 - 3 * 5V6 + 5V6
C = 4V6 - 15V6 + 5V6
C = -6V6