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]$-4x + y = -28$[/tex]
B. [tex]$2x + y = 14$[/tex]
C. [tex]$2x + 8y = 12$[/tex]
D. [tex]$4x - y = -28$[/tex]



Answer :

In this problem, we need to find which equation represents the line [tex]\(\overleftrightarrow{ AC }\)[/tex] that is perpendicular to the line [tex]\(\overleftrightarrow{ DB }\)[/tex]. The given equation of [tex]\(\overleftrightarrow{ DB }\)[/tex] is:
[tex]\[ \frac{1}{2}x + 2y = 12 \][/tex]

First, let's convert this equation into slope-intercept form ([tex]\(y = mx + b\)[/tex]), where [tex]\(m\)[/tex] represents the slope of the line.

[tex]\[ \frac{1}{2}x + 2y = 12 \][/tex]

Isolate [tex]\(y\)[/tex]:
[tex]\[ 2y = -\frac{1}{2}x + 12 \][/tex]

Divide both sides by 2:
[tex]\[ y = -\frac{1}{4}x + 6 \][/tex]

So, the slope of line [tex]\(\overleftrightarrow{ DB }\)[/tex] is [tex]\(-\frac{1}{4}\)[/tex].

Since lines [tex]\(\overleftrightarrow{ DB }\)[/tex] and [tex]\(\overleftrightarrow{ AC }\)[/tex] are perpendicular, the slope of [tex]\(\overleftrightarrow{ AC }\)[/tex] should be the negative reciprocal of [tex]\(-\frac{1}{4}\)[/tex]. To find the negative reciprocal, we flip the fraction and change the sign.

The negative reciprocal of [tex]\(-\frac{1}{4}\)[/tex] is:
[tex]\[ 4 \][/tex]

Now we need to find which of the given options has a slope of 4:

1. [tex]\(-4x + y = -28\)[/tex]

Convert to slope-intercept form:
[tex]\[ y = 4x - 28 \][/tex]
The slope of this line is 4.

2. [tex]\(2x + y = 14\)[/tex]

Convert to slope-intercept form:
[tex]\[ y = -2x + 14 \][/tex]
The slope of this line is -2.

3. [tex]\(2x + 8y = 12\)[/tex]

Convert to slope-intercept form:
[tex]\[ 8y = -2x + 12 \][/tex]
[tex]\[ y = -\frac{1}{4}x + \frac{3}{2} \][/tex]
The slope of this line is -[tex]\(\frac{1}{4}\)[/tex].

4. [tex]\(4x - y = -28\)[/tex]

Convert to slope-intercept form:
[tex]\[ -y = -4x - 28 \][/tex]
[tex]\[ y = 4x + 28 \][/tex]
The slope of this line is 4.

From the above conversions, we see that both option 1 ([tex]\(-4x + y = -28\)[/tex]) and option 4 ([tex]\(4x - y = -28\)[/tex]) have a slope of 4, which matches the requirement for being perpendicular to the line [tex]\(\overleftrightarrow{ DB }\)[/tex].

Therefore, the correct equations of [tex]\(\overleftrightarrow{ AC }\)[/tex] are:
[tex]\[ \boxed{-4x + y = -28 \ \text{and} \ 4x - y = -28} \][/tex]

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