Question

In the given figure Line l₁ is a parallel to Line l₂. If line l₃ is perpendicular to Line l₁, then the slopes of lines l₂ and l₃ respectively are:

Options

• 1, 1

• –1, –1

• 1, –1

• –1, 1

Answer 1

1, –1

Explanation:

The figure shows l₁ inclined at 45° to the x-axis, so slope (l₁) = tan 45° = 1.

Since l₂ || l₁, slope (l₂) = 1. 

A line perpendicular to a line of slope 1 must have slope –1, perpendicular slopes multiply to –1. 

Therefore, the slopes of l₂ and l₃ are 1 and –1 respectively.