Are the pairs parallel, perpendicular, or intersecting

2x - y = 7
3x - 4y = -8

Y
y = -2/3x + 7
-2x - 3y =7

y -6 = 1/4 (x + 2)
y = -4x - 10

Perpendicular parallel. Interesting

1 answer

To determine whether the given pairs of lines are parallel, perpendicular, or intersecting, we can first convert each line into the slope-intercept form (y = mx + b), where m is the slope.

Pair 1:

  1. Line 1: \(2x - y = 7\)

    Rearranging: \[ -y = -2x + 7 \ y = 2x - 7 \]

    • Slope (m1) = 2
  2. Line 2: \(3x - 4y = -8\)

    Rearranging: \[ -4y = -3x - 8 \ y = \frac{3}{4}x + 2 \]

    • Slope (m2) = \(\frac{3}{4}\)

Comparison:

  • Are the slopes equal? No, \(2 \neq \frac{3}{4}\) (not parallel).
  • Are the slopes negative reciprocals? No, \(2 \cdot \frac{3}{4} \neq -1\) (not perpendicular).

Conclusion: Lines intersect.


Pair 2:

  1. Line 1: \(y = -\frac{2}{3}x + 7\)

    • Slope (m1) = \(-\frac{2}{3}\)
  2. Line 2: \(-2x - 3y = 7\)

    Rearranging: \[ -3y = 2x + 7 \ y = -\frac{2}{3}x - \frac{7}{3} \]

    • Slope (m2) = \(-\frac{2}{3}\)

Comparison:

  • Are the slopes equal? Yes, \(-\frac{2}{3} = -\frac{2}{3}\) (parallel).

Conclusion: Lines are parallel.


Pair 3:

  1. Line 1: \(y - 6 = \frac{1}{4}(x + 2)\)

    Rearranging: \[ y - 6 = \frac{1}{4}x + \frac{1}{2} \ y = \frac{1}{4}x + \frac{13}{2} \]

    • Slope (m1) = \(\frac{1}{4}\)
  2. Line 2: \(y = -4x - 10\)

    • Slope (m2) = \(-4\)

Comparison:

  • Are the slopes equal? No, \(\frac{1}{4} \neq -4\) (not parallel).
  • Are the slopes negative reciprocals? Yes, \(\frac{1}{4} \cdot (-4) = -1\) (perpendicular).

Conclusion: Lines are perpendicular.


Summary:

  1. Pair 1: Intersecting
  2. Pair 2: Parallel
  3. Pair 3: Perpendicular