va rog repedeeeeeeeeeee dau corona peste mine repedeee

Răspuns:
8.
a*b+a*c+a=165
a(b+c)+a=165
a*10+a=165
11a=165
a=15
9.
a+b=20 =>3*a+3*b=3*20=>3a+3b=60 (1)
b+c=30=>4*b+4*c=4*30=>4a+4b=120 (2)
Adunam relatiile 1 si 2: 3a+3b+4b+4c=60+120 => 3a+7b+4c=180