Răspuns :
17380+(9909 +a)=43165
9909 + a = 43165-17380
9909 + a = 25875
a = 25875 - 9909
a = 15876
17380+(9909+a)=43165
9909+a=43165-17380=25785
a=25785-9909
a=15876
17380+(9909 +a)=43165
9909 + a = 43165-17380
9909 + a = 25875
a = 25875 - 9909
a = 15876
17380+(9909+a)=43165
9909+a=43165-17380=25785
a=25785-9909
a=15876