The line through the points (h, 3) and (4, 1) intersects the line 7x − 9y −19 = 0. at right angle. Find the value of h.
Let the slope of the line passing through (h, 3) and (4, 1) be m1
Then,
Let the slope of line 7x – 9y – 19 = 0 be m2
⇒ 7x – 9y – 19 = 0
Since, the given lines are perpendicular
Therefore, m1 × m2 = -1
⇒ -14 = -1 × (36 – 9h)
⇒ 36 – 9h = 14
⇒ 9h = 36 – 14
⇒ h = 22/9
∴ h = 22/9