Numerical answer
Find the perpendicular distance between the parallel lines 8x + 6y = 20 and 4x + 3y + 9 = 0.
Show answer and solution
Answer: 3.8
Make the coefficients match. Multiply the second equation by 2: 8x + 6y + 18 = 0. The first, in the same form, is 8x + 6y − 20 = 0.
Distance = |c₁ − c₂|/√(a² + b²) = |−20 − 18|/√(64 + 36) = 38/10 = 3.8.
Trap: the lines must first be scaled so a and b match exactly before applying the distance formula.
Distance = |c₁ − c₂|/√(a² + b²) = |−20 − 18|/√(64 + 36) = 38/10 = 3.8.
Trap: the lines must first be scaled so a and b match exactly before applying the distance formula.
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