anonymous 3 years ago Find the coordinates of the point (-5,7) when it is reflected across the line y=11.

1. anonymous

Use mid point formula.

2. anonymous

But don't you need more than one coordinate?

3. anonymous

mirror being mid point of the line joining the two points. $\left\{ -5,11 \right\}$ now $-5=\frac{x2-x1 }{ 2 }$ and $11=\frac{ y2-y1 }{ 2 }$

4. anonymous

you know x1 and y1 find x2 and y2

5. anonymous

Did you get it .

6. anonymous

I completely understand what you're saying, but I honestly have no idea how to solve for x2 and y2. I remember learning this, but I haven't used it in 2 years.

7. anonymous

did you get the idea behind mid point

8. anonymous

Yes I do!

9. anonymous

Then take the given point as the first point in the case i.e (-5,7)

10. anonymous

now use x1=-5 and y1=7

11. anonymous

now use the formula that I have already posted

12. anonymous

Wait, so wouldn't it be (-5,-7)?

13. anonymous

Nevermind, let me resolve quick.

14. anonymous

did you get is answer as (-5,15). If not I can give us an another approach