Question

Dois amigos caminham no plano xy, ao longo de retas paralelas cujas equações são 2x + 17y = 7 e -x + my = 1. Então, o valor de "m" é:

A) 11/2
B) 13/2
C) 15/2
D) 19/2
E) Nenhuma das respostas anteriores

Answer 1

$\large\boxed{\begin{array}{l}\rm r:2x+17y=7\\\rm r: y=-\dfrac{2}{17}x+\dfrac{7}{17}\longrightarrow m_r=-\dfrac{2}{17}\\\rm s:-x+my=1\\\rm s: y=\dfrac{1}{m}x+\dfrac{1}{m}\longrightarrow m_s=\dfrac{1}{m}\\\\\rm s\parallel r\iff m_s=m_r\\\rm\dfrac{1}{m}=-\dfrac{2}{17}\\\\\rm m=-\dfrac{17}{2}\\\huge\boxed{\boxed{\boxed{\boxed{\rm\dagger\red{\maltese}~\blue{alternativa~E}}}}}\end{array}}$