**Q: **Is slope calculated by finding the ratio of the "vertical change" to the "horizontal change" between two distinct points on a line? ¶

**A: **Yes.

**Q: **Are slopes -1? ¶

**A: **Yes, So these two lines are perpendicular.

**Q: **Is slope central to differential calculus? ¶

**A: **Yes.

**Q: **Are slopes equal or they both are vertical and therefore both have undefined slopes? ¶

**A: **Yes.

**Q: **Is slope negative? ¶

**A: **Yes, and the direction of the line is decreasing.

**Q: **Is slope zero? ¶

**A: **Yes.

**Q: **Is slope positive? ¶

**A: **Yes, and the direction of the line is increasing.