Răspuns :
a - ( 5 × 7 ) = 35
a - 35 = 35
a = 35 + 35
a = 70
a + ( 5 × 9 ) = 72
a + 45 = 72
a = 72 - 45
a = 27
a - 35 = 35
a = 35 + 35
a = 70
a + ( 5 × 9 ) = 72
a + 45 = 72
a = 72 - 45
a = 27