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Given that the straight lines (kx – 5y + 6 = 0) and (mx +…

Given that the straight lines (kx – 5y + 6 = 0) and (mx + ny – 1 = 0) are parallel, find a relationship connecting the constants m, n and k.

  • A.
    5n – km = 0
  • B.
    kn + 5m = 0
  • C.
    5n + km = 0
  • D.
    kn – 5m = 0
Correct Answer: Option B
Explanation

Two lines are parallel if and only if their slopes are equal.

(kx – 5y + 6 = 0 implies 5y = kx + 6)

(y = frac{k}{5}x + frac{6}{5})

(Slope = frac{k}{5})

(mx + ny – 1 = 0 implies ny = 1 – mx)

(y = frac{1}{n} – frac{m}{n}x)

(Slope = -frac{m}{n})

(Parallel implies frac{k}{5} = -frac{m}{n})

(-5m = kn implies 5m + kn = 0)