Question

Se p e q são tais que {p- q = 4 p + q = 12 , então quanto vale p × q - 2 ?

Answer 1

Resposta:

30

Explicação passo a passo:

$\left \{ {{p-q=4} \atop {p+q=12}} \right. \\\\\\\left \{ {{p-q=4} \atop {q=12-p}} \right. \\\\\\\left \{ {{p-(12-p)=4} \atop {q=12-p}} \right. \\\\\\\left \{ {{p-12+p=4} \atop {q=12-p}} \right. \\\\\\\left \{ {{p+p=4+12} \atop {q=12-p}} \right. \\\\\\\left \{ {{2p=16} \atop {q=12-p}} \right. \\\\\\\left \{ {{p=\frac{16}{2} } \atop {q=12-p}} \right. \\\\\\\left \{ {{p=8 } \atop {q=12-p}} \right. \\\\\\\left \{ {{p=8 } \atop {q=12-8}} \right. \\\\\\\left \{ {{p=8 } \atop {q=4}} \right.$

$p\times q-2\\\\\\8\times4-2\\\\\\32-2\\\\\\\bold{30}$