First, solve for y
[tex]\begin{gathered} 2y=-4x+18 \\ y=-2x+9 \end{gathered}[/tex]the slope of this line is -2, because is the coefficient of x
Two perpendicular lines have the same slope but inverted and with a different sign
so, the slope of the perpendicular line is
[tex]-2\longrightarrow\frac{1}{2}[/tex]1/2
