Question

Are these lines `8x - y = 7 and x + 8y = 7` parallel, perpendicular or neither?

Answer 1

Perpendicular.

Explanation:

Parallel lines have the same slope.

Perpendicular lines have slopes that are negative reciprocals of each other.

If you manipulate the second equation, you get:

`8y=-x+7`

By dividing. By `8` you get:

`y=-\frac{1}{8]x+7`

The slope here is the negative receiprocal of `8`, which is the slope of the other line.

`\therefore` the lines are perpendicular.