How to find area of parallelogram with coordinates of verticles?

You find a parallelogram area by this formula:

Where b is its base and h, its height.
You get b's value applying distance between two points formula.
If A and B points form the base:


And h is the perpendicular distance between both bases.
You can visit next link to know further about it:
https://www.ck12.org/geometry/Distance-Between-Parallel-Lines/lesson/Distance-Between-Parallel-Lines
-GEOM/

And in attached picture you can find an example in progress you may want to finish.

Abit confused about what you mean, but i think you might be referring to slope intercept form: y = mx + bin that case b, or the y intercept is already given.(0,-1)find the slope by using the formulay2 - y1/x2 - x1the final slope will be 4/2, equivalent to 2.now your equation should look like thisy = 4/2x -1sorry if this didn’t you out!