## College Algebra (10th Edition)

$m_1=m_2$; y-intercepts; $m_1 \cdot m_2=-1$
RECALL: (1) Parallel lines have equal slopes but have different y-intercepts (2) Perpendicular lines have slopes whose product is $-1$ Thus, the missing expressions in the given statements are (in order): $m_1=m_2$; y-intercepts; $m_1 \cdot m_2=-1$