Question
Line L has equation $y = 4 – 5x$.
Find the equation of a line that is perpendicular to line L and passes through the point (0, 6).
▶️ Answer/Explanation
Solution
Ans: $y = \frac{1}{5}x + 6$
1. Original slope is -5, so perpendicular slope is $\frac{1}{5}$ (negative reciprocal)
2. Using point-slope form with point (0,6): $y – 6 = \frac{1}{5}(x – 0)$
3. Simplify to get $y = \frac{1}{5}x + 6$
Question
Find the gradient of a line that is perpendicular to 8y + 4x = 5.
▶️ Answer/Explanation
Answer: 2
First, find the gradient of the given line: rearrange to \(y = -\frac{1}{2}x + \frac{5}{8}\) (gradient = \(-\frac{1}{2}\)). The perpendicular gradient is the negative reciprocal, so \(2\).