Determine whether the pair of lines is parallel, perpendicular, or neither.

[tex]\[ \begin{array}{l} 9x + 3y = 12 \\ 6x + 2y = 9 \end{array} \][/tex]

A. parallel
B. perpendicular
C. neither



Answer :

To determine whether the given pair of lines is parallel, perpendicular, or neither, we start by analyzing the two given equations of the lines:

1. [tex]\(9x + 3y = 12\)[/tex]
2. [tex]\(6x + 2y = 9\)[/tex]

The first step is to rewrite these equations in their slope-intercept form ([tex]\(y = mx + b\)[/tex]) to identify the slopes of the lines. This form is helpful because, in slope-intercept form, the coefficient of [tex]\(x\)[/tex] represents the slope ([tex]\(m\)[/tex]) of the line.

### Step 1: Convert the first equation to slope-intercept form

Starting with:
[tex]\[9x + 3y = 12\][/tex]

We solve for [tex]\(y\)[/tex] by isolating [tex]\(y\)[/tex] on one side of the equation:

[tex]\[3y = -9x + 12\][/tex]

Now, divide both sides by 3 to get:
[tex]\[y = -3x + 4\][/tex]

Thus, the slope [tex]\(m_1\)[/tex] of the first line is [tex]\(-3\)[/tex].

### Step 2: Convert the second equation to slope-intercept form

Next, we take:
[tex]\[6x + 2y = 9\][/tex]

Similar to the previous step, solve for [tex]\(y\)[/tex]:

[tex]\[2y = -6x + 9\][/tex]

Divide both sides by 2:
[tex]\[y = -3x + \frac{9}{2}\][/tex]

Thus, the slope [tex]\(m_2\)[/tex] of the second line is also [tex]\(-3\)[/tex].

### Step 3: Compare the slopes of the lines

Now that we have the slopes, we can compare them:
- [tex]\(m_1 = -3\)[/tex]
- [tex]\(m_2 = -3\)[/tex]

### Step 4: Conclusion

If two lines have the same slope, they are parallel. Perpendicular lines would have slopes that are negative reciprocals of each other (e.g., [tex]\(m\)[/tex] and [tex]\(-\frac{1}{m}\)[/tex]).

Given that both slopes are equal, we conclude:
The lines are parallel.

Thus, the correct answer is:
A. parallel

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