Question

How to solve (-1,8) and (8,-8)

Answer 1

Step-by-step explanation:

1. If you are trying to find a linear equation from those two points, use the equation y2-y1 over x2-x1. y2-y1 just means the second point's y coordinate minus the first point's y coordinate (same goes for x2-x1).

2. So if you were to plug the coordinates into the equation, it would be: -8-8 over 8-(-1).

3. Solve to get -16/9 because -8-8=-16 and 8-(-1)=9, so -16/9. -16/9 is the slope of the line in the y=mx +b equation.

4. It would be written like y=-16/9x +b

5. Now we need to find b which is the y-intercept. To find this pick one of the points (we'll just do (-1,8)), and plug in the x and y coordinates and solve for b.

• 8=-16/9(-1) +b
• multiply -16/9 by -1 which is 16/9
• subtract from both sides for it to be 8-16/9 on the left side which is 6 2/9, and that is b

6. The complete equation is now y=-16/9x + 6 2/9