Select the correct answer.

A graphic designer is creating a logo for a client. Lines [tex]\(\overleftrightarrow{DB}\)[/tex] and [tex]\(\overleftrightarrow{AC}\)[/tex] are perpendicular. The equation of [tex]\(\overleftrightarrow{DB}\)[/tex] is [tex]\(\frac{1}{2}x + 2y = 12\)[/tex]. What is the equation of [tex]\(\overleftrightarrow{AC}\)[/tex]?

A. [tex]\(2x + 8y = 12\)[/tex]
B. [tex]\(-4x + y = -28\)[/tex]
C. [tex]\(4x - y = -28\)[/tex]
D. [tex]\(2x + y = 14\)[/tex]



Answer :

To determine the equation of the line perpendicular to [tex]\(\overleftrightarrow{DB}\)[/tex], we proceed step by step as follows:

1. Convert the equation [tex]\( \frac{1}{2} x + 2 y = 12 \)[/tex] into slope-intercept form [tex]\( y = mx + c \)[/tex].
[tex]\[\frac{1}{2} x + 2 y = 12\][/tex]

Isolate [tex]\( y \)[/tex] on one side:
[tex]\[ 2 y = -\frac{1}{2} x + 12 \][/tex]
[tex]\[ y = - \frac{1}{4} x + 6 \][/tex]
Thus, the equation is in the form [tex]\( y = mx + c \)[/tex] where the slope [tex]\( m \)[/tex] is [tex]\( -\frac{1}{4} \)[/tex].

2. Find the slope of the perpendicular line.
For two lines to be perpendicular, the product of their slopes must be [tex]\(-1\)[/tex]. If the slope of [tex]\(\overleftrightarrow{DB}\)[/tex] is [tex]\( -\frac{1}{4} \)[/tex], then let the slope of [tex]\(\overleftrightarrow{AC}\)[/tex] be [tex]\( m' \)[/tex].
[tex]\[ m \cdot m' = -1 \][/tex]
[tex]\[ \left( -\frac{1}{4} \right) \cdot m' = -1 \][/tex]
Solving for [tex]\( m' \)[/tex]:
[tex]\[ m' = 4 \][/tex]
Therefore, the slope of [tex]\(\overleftrightarrow{AC}\)[/tex] is [tex]\( 4 \)[/tex].

3. Construct the equation of the perpendicular line [tex]\( \overleftrightarrow{AC} \)[/tex] using the slope [tex]\( 4 \)[/tex].
The general form of the line's equation with slope [tex]\( 4 \)[/tex] is:
[tex]\[ y = 4x + c \][/tex]
Convert this into standard form [tex]\(Ax + By = C\)[/tex]:
[tex]\[ 4x - y = -c \][/tex]

4. Compare the given options to determine which matches the form [tex]\( 4x - y = C \)[/tex].
- [tex]\( 2x + 8y = 12 \)[/tex]: This can be rewritten but doesn't fit the [tex]\( 4x - y = C \)[/tex] form directly.
- [tex]\( -4x + y = -28 \)[/tex]: When rearranged, this looks like [tex]\( y = 4x - 28 \)[/tex], but the signs are incorrect.
- [tex]\( 4x - y = -28 \)[/tex]: This is already in the correct form.
- [tex]\( 2x + y = 14 \)[/tex]: Doesn't fit the [tex]\( 4x - y = C \)[/tex] form directly.

Thus, the correct equation for the line [tex]\(\overleftrightarrow{AC}\)[/tex] is:
[tex]\[ 4x - y = -28 \][/tex]

So, the correct answer is:
[tex]\[ \boxed{4 x - y = -28} \][/tex]