## 3psilon 3 years ago Standard form for a parabola with this equation! Help please!

1. 3psilon

$y = -\frac{ 1 }{ 4 }x^{2} -x + \frac{ 1 }{ 4 }$

2. 3psilon

I don't get the completing the square part

drawing? can't see equation

4. hartnn

that equation is in standard form, u need to get it in vertex form ?

5. 3psilon

yes

6. hartnn

-1/4(x^2+4x)+1/4 what to add and subtract ?

7. 3psilon

subtract 1/4

8. hartnn

we add and subtract the square of half of co-efficient of x so here, what is half of 4 ?

9. 3psilon

2

10. hartnn

and its square ?

11. 3psilon

4

12. hartnn

so what will u add and subtract ?

13. 3psilon

Do you subtract the square?

14. hartnn

u add and subtract the 4 like this: -1/4(x^2+4x+4 -4)+1/4 can u go ahead ?

15. 3psilon

y-1/4 +4 = -1/4(x^2+4x -4)

16. hartnn

y-1/4 -4(1/4) = -1/4(x^2+4x +4)

17. 3psilon

why -4(1/4) on the left???

18. hartnn

y=-1/4(x^2+4x+4 -4)+1/4 = -1/4 (x^2+4x+4) -1/4 (-4) +1/4 y-1/4 -1/4(4) = -1/4(x^2+4x+4) confusing ?

19. 3psilon

why did you not add it to both sides? why subtract? it says -1/4(-4)

20. 3psilon

Ohh I see it now

21. 3psilon

Wow thank you so much

22. hartnn

u can continue to get the vertex form, right ?

23. 3psilon

yess It is quite easy now. Thank you so much :) I can sleep now haha

24. hartnn

welcome ^_^