Question

Find the value of ‘a’, if the line through (– 2, 3) and (8, 5) is perpendicular to y = ax + 2

Answer 1

Given points are (– 2, 3) and (8, 5)

Slope of a line = `(y_2 - y_1)/(x_2 - x_1)`

= `(5 - 3)/(8 + 2)`

= `2/10`

= `1/5`

Slope of a line y = ax + 2 is “a”

Since two lines are ⊥^r

m₁ × m₂ = – 1

`1/5 xx "a"` = – 1

⇒ `"a"/5` = – 1

⇒ a = – 5

∴ The value of a = – 5