## InsanelyChaotic 2 years ago Solve x2 + 6x + 7 = 0. Options are below!!!

1. InsanelyChaotic

2. InsanelyChaotic

3. InsanelyChaotic

4. InsanelyChaotic

5. hartnn

6. hartnn

Compare your quadratic equation with $$ax^2+bx+c=0$$ find a,b,c then the two roots of x are: $$\huge{x=\frac{-b \pm \sqrt{b^2-4ac}}{2a}}$$

7. Yahoo!

$\frac{ -b \pm \sqrt{b^2-4ac} }{ 2a }$

8. InsanelyChaotic

How do I apply that to this problem? Like i'm having trouble setting it up

9. hartnn

none of the options are correct b^2-4ac = 36-28 = 8 so there should be sqrt 8 in options or sqrt 2

10. hartnn

couldn't u find, a,b,c ?

11. InsanelyChaotic

Those are the only options.......

12. hartnn

then your question must be incorrect

13. hartnn

check it

14. hartnn

15. hartnn

for this its, (-6+- sqrt 8)/2 = (-3+- sqrt2)

16. InsanelyChaotic

Solve x2 + 6x + 7 = 0

17. hartnn

for that (-3+- sqrt2)

18. InsanelyChaotic

Oh my goodnes!!!!1 I'm SO sorry

19. InsanelyChaotic

i see what occurred

20. InsanelyChaotic

the question is: Solve 3x2 + 4x = 2

21. hartnn

right, 3x^2+4x-2=0 now apply the formula can u find,a,b,c first ?

22. InsanelyChaotic

3, 2, 4?

23. hartnn

|dw:1352747869498:dw|

24. InsanelyChaotic

a = 3 b = 4 c = -2

25. hartnn

yes. now what is b^2-4ac = ?

26. InsanelyChaotic

one moment

27. InsanelyChaotic

16 - 4(3)(-2)???

28. InsanelyChaotic

four times a c? or four times a times c?

29. hartnn

yes, evaluate that

30. InsanelyChaotic

It equals 40

31. hartnn

yes, now put all values in formula and tell me what u get for x.

32. InsanelyChaotic

ok

33. InsanelyChaotic

This is how I set it up: -4+sq root 4^2-4(3)(-2)/2(3)

34. InsanelyChaotic

= 36

35. InsanelyChaotic

@hartnn

36. hartnn

x1=[-4 + sqrt (40)] / (2*3) = ? x2=[-4 - sqrt (40)] / (2*3) = ?

37. hartnn

got that ^ ?

38. InsanelyChaotic

Yes!! :)

39. hartnn

40. InsanelyChaotic

3.7

41. InsanelyChaotic

-13.4 for the second

42. hartnn

from the options ? 3.7 is not in options keep sqrt 40 as 2sqrt 10 only

43. InsanelyChaotic

option b

44. hartnn

absolutely correct! got it ?

45. InsanelyChaotic

YES!!!!!!!!!!!! It makes sense! why couldn't I see that on my own?? Thank you!!!!!!