Question

a+b=30
a+c=40
b+c=50

a,b,c??

Tema fratelui meu,help :)) Stiu,e usor,dar habar nu mai am

Answer 1

a+b+b+c+a+c=30+40+50 rezulta 2a+2b+2c=120
2a+2b+2c=120
2(a+b+c)=120
a+b+c=60
a=60-b+c=60-50=10
b=60-a+c=60-40=20
c=60-a+b=60-30=30

Answer 2

$\displaystyle a+b=30 \\ a+c=40 \\ b+c=50 \\ a+b+a+c+b+c=30+40+50 \Rightarrow 2a+2b+2c=120 \Rightarrow \\ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\Rightarrow 2(a+b+c)=120 \Rightarrow a+b+c= \frac{120}{2} \Rightarrow \\ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\Rightarrow \boxed{a+b+c=60} \\ a+b+c=60 \Rightarrow 30+c=60 \Rightarrow c=60-30 \Rightarrow \boxed{c=30} \\ a+c=40 \Rightarrow a+30=40 \Rightarrow a=40-30 \Rightarrow \boxed{a=10}$
$a+b=30 \Rightarrow 10+b=30 \Rightarrow b=30-10 \Rightarrow \boxed{b=20} \\ Verificare : 10+20+30=30+30=\boxed{60}$