## mopsy510 2 years ago I need help with my algebra homework! It has to do with "Completing a Square." Please help!

1. NotTim

what exactly is the qun

2. mopsy510

3x^2-15x=0

3. blahblah_who_cares

use perfect squares.

4. mopsy510

Idk how kinda

5. blahblah_who_cares

oh wait. nvm. this is a bad example for perfect squares. use the quadratic formula

6. mopsy510

7. mopsy510

What?

8. AravindG

A quadratic equation is of the form \[ax^2+bx+c=0\] By method of completing the square , we write this as \[a(x-h)^2+constant\]

9. blahblah_who_cares

do not complete the square on this problem. the b is not divisible by 2.

10. mopsy510

So if i dont complete the suare what do i do?

11. blahblah_who_cares

the quadratic equation. which i have written.

12. blahblah_who_cares

|dw:1359606249803:dw|

13. blahblah_who_cares

that is the formula^^^

14. mopsy510

So its |dw:1359606358086:dw|

15. mopsy510

?

16. blahblah_who_cares

no. because u do not have a c then last part of the term in the square root should be o. it should just be rad 15^2.

17. blahblah_who_cares

|dw:1359606587124:dw|

18. mopsy510

19. blahblah_who_cares

nope. u have to simplify. u should come out with 2 answers for x.

20. mopsy510

Ok

21. mopsy510

Why is it over 2?

22. blahblah_who_cares

oh whoops. my bad. it should be over 6

23. mopsy510

Why is it over 6 then?

24. blahblah_who_cares

because ur a is 3. for the standard equation it is ax^2+bx+c

25. mopsy510

Ohh so you have to multiply it by 2?

26. blahblah_who_cares

yah

27. mopsy510

ohh

28. mopsy510

Can you help me with 16y^2+25=25

29. blahblah_who_cares

are u sure u arent saying 16y^2+25y=25?

30. mopsy510

Nope its just 25

31. blahblah_who_cares

well that makes it simple. what do you think u have to do?

32. mopsy510

I think i have to subtract 25 from each side so it becomes 16y^2=0

33. blahblah_who_cares

indeed

34. blahblah_who_cares

and what is the only possible answer for y?

35. mopsy510

16y^2

36. mopsy510

?

37. blahblah_who_cares

no. there is only 1 possible answer in the world for the term y. So what do you think y equals.

38. mopsy510

196

39. blahblah_who_cares

so what u are telling me is that 16*196^2=0?

40. mopsy510

Ohh nvm. Is it 0?

41. blahblah_who_cares

indeed.

42. mopsy510

Isn't it suppose to have 2 answers?

43. blahblah_who_cares

for this equation no. for the previous one yes.

44. mopsy510

Ok. How would i complete the square for the equation y^2-3y?

45. blahblah_who_cares

u would not want to complete the square for it unless u have to. do u have to?

46. mopsy510

Yup

47. mopsy510

It just says "complete the square"

48. mopsy510

It doesn't say solve but the next equations say to solve

49. blahblah_who_cares

ok here is the way u would do it. u would first make the equation equal to zero. Then u get half of b and square it. and the square to both sides. in this case it would be 1.5^2. then you would get (x+1.5)^2=1.5^2. Square root. x+1.5=1.5 Something like that. my math may be wrong because im starting to feel not that great. Hope that helped.

50. mopsy510

Ok thanks