Question

Qual das retas a seguir é perpendicular a reta r: 2x – 4y + 5 = 0?

Answer 1

$2x-4y+5= 0 \\ \\ -4y= -2x-5 \\ \\ y= \dfrac{-2}{-4} x-\dfrac{5}{-4} \\ \\ \\ y= +\dfrac{1}{2} x+\dfrac{5}{4} \\ \\ \\ Pendente\to +\dfrac{1}{2} \\ \\ \\ perpendicular \to pendente\ -2$