Seven of 200 digital video recorders DVR in an inventory are known to be defective

First set are parallel, second are perpendicular, third are perpendicular, fourth are neither.

*If you can't remember the rules, or want to check your answers, I would type them into a graphing calculator. It will easily tell you which category they're in. (desmos.com)*

Step-by-step explanation:

1. Same slope (6/5) = parallel

2. Reciprocal (flipped) slope, opposite signs

3. Reciprocal (flipped) slope, opposite signs

4. Neither, the slopes aren't the same or flipped

When you flip the slopes (3/4 becomes 4/3) and change a sign, the lines will always be perpendicular.

Hope it helps :)