Question

va rog sa ma ajutati la acest exercitiu dau coronita
fie a,b,c, apartine lui R,c nu e egal cu 3,astfel incat a+b+2c=4 si 3a-2b+c=7 aratati ca
a.4a-b+3c=11
b.a+b+2c supra 2a-3b-c= 4 pe 3

Answer 1

$\left \{ {{e1:a+b+2c=4} \atop {e2:3a-2b+c=7}} \right. + \\ e1+e2 <=> a+3a+b-2b+2c+c=4+7 <=> 4a-b+3c=11 \\ e2-e1 <=>3a-a-2b-b+c-2c=7-4 <=>2a-3b-c=3 \\ => \frac{a+b+2c}{2a-3b-c}= \frac{4}{3}$