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

Nov 29, 2017

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:

$8 y = - x + 7$

By dividing. By $8$ you get:

$y = - \setminus \frac{1}{8} x + 7$

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

$\setminus \therefore$ the lines are perpendicular.