Line [tex]$m$[/tex] has a [tex]$y$[/tex]-intercept of [tex][tex]$c$[/tex][/tex] and a slope of [tex]$\frac{p}{q}$[/tex], where [tex]$p \ \textgreater \ 0$[/tex], [tex][tex]$q \ \textgreater \ 0$[/tex][/tex], and [tex]$p \neq q$[/tex].

What is the slope of a line that is perpendicular to line [tex]$m$[/tex]?

A. [tex]$\frac{q}{p}$[/tex]
B. [tex][tex]$-\frac{q}{p}$[/tex][/tex]
C. [tex]$\frac{p}{q}$[/tex]
D. [tex]$-\frac{p}{q}$[/tex]



Answer :

To determine the slope of a line that is perpendicular to line [tex]\( m \)[/tex], we need to understand the relationship between the slopes of perpendicular lines.

Let's start with the given information:

- Line [tex]\( m \)[/tex] has a slope of [tex]\( \frac{p}{q} \)[/tex], where [tex]\( p > 0 \)[/tex] and [tex]\( q > 0 \)[/tex].

When two lines are perpendicular, the product of their slopes is [tex]\(-1\)[/tex]. In other words, if the slope of one line is [tex]\( m_1 \)[/tex] and the slope of the line perpendicular to it is [tex]\( m_2 \)[/tex], then:

[tex]\[ m_1 \times m_2 = -1 \][/tex]

Here, the slope of line [tex]\( m \)[/tex] is [tex]\( \frac{p}{q} \)[/tex]. Let's denote this as [tex]\( m_1 \)[/tex]:

[tex]\[ m_1 = \frac{p}{q} \][/tex]

We need to find [tex]\( m_2 \)[/tex], the slope of the line perpendicular to line [tex]\( m \)[/tex]. Using the relationship between perpendicular slopes:

[tex]\[ \left(\frac{p}{q}\right) \times m_2 = -1 \][/tex]

To solve for [tex]\( m_2 \)[/tex], divide both sides of the equation by [tex]\( \frac{p}{q} \)[/tex]:

[tex]\[ m_2 = -\frac{1}{\left(\frac{p}{q}\right)} \][/tex]

Since dividing by a fraction is the same as multiplying by its reciprocal, this simplifies to:

[tex]\[ m_2 = -\frac{q}{p} \][/tex]

Therefore, the slope of the line perpendicular to line [tex]\( m \)[/tex] is [tex]\( -\frac{q}{p} \)[/tex].

Among the given choices:

A. [tex]\( \frac{q}{p} \)[/tex]
B. [tex]\( -\frac{q}{p} \)[/tex]
C. [tex]\( \frac{p}{q} \)[/tex]
D. [tex]\( -\frac{p}{q} \)[/tex]

The correct answer is:

B. [tex]\( -\frac{q}{p} \)[/tex]