Question

What is the slope of a line that contains the points (-1, 9) And 5, 21)

Answer 1

It's very simple, all you need is to plug it in the slope formula.

Slope formula:   (y2 - y1) / (x2 - x1)

Then, plug

(9,21) / (-1,5)

Lastly, you solve, which will give you the slope as 0.5.