Question

The slope of line m is 7/8. If n⊥m, what is the slope of line n?

A) 7/8
B) 8/7
C) -7/8
D) -8/7

Answer 1

Hey there !

When two lines are perpendicular , the product of their slope is -1 ,

m1 × m2 = -1
7/8 × m2 = -1

m2 = -8/7 Ans.

Answer 2

`k:y=m_1x+b\\l:y=m_2x+c\\\\l\ \perp\ k\iff m_1m_2=-1`
We have:

`m_1=(7)/(8);\ m_2=?`
Substitute:

`(7)/(8)m_2=-1\ \ \ \ |\cdot(8)/(7)\\\\m_2=-(8)/(7)`
Answer: D)