Chapter 4 - Writing Linear Functions - 4.3 - Writing Equations of Parallel and Perpendicular Lines - Exercises - Page 191: 18

Line $b$ has a slope of $-\frac{1}{6}$, the negative reciprocal of $6$, so it is perpendicular to line $a$.

Line $a:$ $\Rightarrow y=6x-2$. Slope is $m_a=6$ Line $b:$ $\Rightarrow 6y=-x$. Slope intercept form is $\Rightarrow y=-\frac{1}{6}x+0$. Slope is $m_b=-\frac{1}{6}$ Line $c:$ $\Rightarrow y+6x=1$. Slope intercept form is $\Rightarrow y=-6x+1$. Slope is $m_c=-6$ Line $b$ has a slope of $-\frac{1}{6}$, the negative reciprocal of $6$, so it is perpendicular to line $a$.