i still didn't get it
All you have to do is get urself back to the original equation, and see what y needs to be in order to get back to that equation. If you dont understand that then do this:
1. Make 0 the subject of the formula
2. Then get it into a form like this :
![ax^2+bx+c](https://studentforums.biz/cgi-bin/mimetex.cgi?ax^2+bx+c)
3. Now, compare it to the original equation,
![x^2-8x-7](https://studentforums.biz/cgi-bin/mimetex.cgi?x^2-8x-7)
4. Now determine what y needs to be in order to get that value.
5. Also remember, if
![2x^2-16x-9=0](https://studentforums.biz/cgi-bin/mimetex.cgi?2x^2-16x-9=0)
, then
![x^2-8x-4.5](https://studentforums.biz/cgi-bin/mimetex.cgi?x^2-8x-4.5)
is also equal to 0.
6. That is often a problem many of my frnds faced.
Hope that helped.