Question

se stie ca: ab+ac+a=165 si b+c=10. aflati a

Answer 1

in prima ecuatie dam factor comun pe a => a(b+c+1) = 165, din moment ce b=c= 10 atunci a(10+1) = 165 si atunci 11a=165 =>  a = 165:11 => a =15

Answer 2

$\displaystyle ab+ac+a=165 \\ b+c=10 \\ a=? \\ ab+ac+a=165 \\ a(b+c)+a=165 \\ 10a+a=165 \\ 11a=165 \\ a=165:11 \\ \boxed{a=15}$