Răspuns :
a - 9 x 3 = 40
a - 27 = 40
a = 27 + 40
a = 67
b + 7 x 4 = 51
b + 28 = 51
b = 51 - 28
b = 13
5 x 6 + a - 9 x 4 = 17
30 + a - 36 = 17
30 + a = 53
a = 53 - 30
a = 23
Exlpicatii:
a) a-9×3=40
a=40+9×3
a=40+27
a=67
b) b+7×4=51
b=51-7×4
b=51-28
b=23
c) ?