## anonymous 4 years ago finding missing endpoints: is there a way to do it algebraically? http://www.youtube.com/watch?v=d51p_8xQQZ0 so you can draw a number line to see how far each number is from each other, but is there a faster way to do it?

1. anonymous

ignore this video. you can find the endpoint using algebra or just thinking. you have an actual problem to solve?

2. anonymous

Endpoint: (−9, −1), midpoint: (8, 14)

3. anonymous

you want algebra or think method?

4. anonymous

algebra

5. anonymous

or whatever you were typing

6. anonymous

we can do both for first coordinate solve $\frac{x-9}{2}=8$ and for second solve $\frac{y-1}{2}=14$

7. anonymous

because midpoint you use $\frac{x_1+x_2}{2}$ for the first coordinate and $\frac{y_1+y_2}{2}$ for the second. so if you know the answer you can find the first or second coordinate

8. anonymous

oh i see i got it right, you subtracted because they're negative?

9. anonymous

thank you :'} you're very good at math don't ever stop what you're doing

10. anonymous

yes i "subtracted" because both were negative. if they had been positive i would have added.

11. anonymous

thank you for the compliment