Question

Se (x,y)=(1,2) é a unica soluçao do sistema {ax+by=11,entao os valores
{bx-ay=3 de A e B são???

Answer 1

$Se~~ (x,y) = (1,2),~~ ent\~ao:$
$x= 1~~~~~e~~~~y = 2$

$substituindo~~os~~valores~~no~~sistema~~ temos:$

$\left \{ {{a.1+ b.2=11} \atop {b.1 -a.2=3}} \right.$
$fica:$
$\left \{ {{a+\not2b=11} \atop {a-\not2b=3}} \right. ~~~~~~resolvendo~~ por~~adi{\c~c}\~ao$
$2a = 14$
$a= \frac{14}{2}$
$\boxed{a= 7}$

$7 + 2b =11$
$2b =11-7$
$2b =4$
$b= \frac{4}{2}$
$\boxed{b= 2}$