Question

Which best describes the relationship between the lines with equations 2x – 9y = 1 and x + 8y = 6?

A. perpendicular
B. neither perpendicular nor parallel
C. parallel
D. same line

Answer 1

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Answer:

B. neither perpendicular nor parallel

Explanation:

If the lines were perpendicular, the coefficients would be swapped and one negated. (You would have 8x -y = c, or 9x +2y = c in the system.)

If the lines were parallel, the coefficients in the two equations would only differ by a common factor. (Both equations would reduce to 2x -9y = c, or x +8y = c.)

The lines are not the same line (coefficients are different).

So, the only reasonable description is ...

neither perpendicular nor parallel