neverforgetvivistee Group Title 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? 2 years ago 2 years ago

1. satellite73 Group Title

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

2. neverforgetvivistee Group Title

Endpoint: (−9, −1), midpoint: (8, 14)

3. satellite73 Group Title

you want algebra or think method?

4. neverforgetvivistee Group Title

algebra

5. neverforgetvivistee Group Title

or whatever you were typing

6. satellite73 Group Title

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

7. satellite73 Group Title

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. neverforgetvivistee Group Title

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

9. neverforgetvivistee Group Title

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

10. satellite73 Group Title

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

11. satellite73 Group Title

thank you for the compliment