## Katelynmorris 2 years ago solve the quadratic equation. x^2-3x=4

1. shamil98

x^2 - 3x - 4 = 0 factor it.

2. swissgirl

We first need to set it up in the form \(ax^2+bx+c=0\)

3. swissgirl

Well ya like @shamil98 has shown we subtract 4 from both sides to achieve this

4. Katelynmorris

Ok I got that. I have x^2-3x-4=0 but I am not sure where to go from there.

5. shamil98

you can use the quadratic formula or just factor it to (x+b)(x-b) form. and then solve for (x+b)=0 and (x-b) = 0 to get your solutions

6. swissgirl

We need to find 2 numbers that when you add them they equal -3 and when you multiply them they equal -4

7. Katelynmorris

Well that would be -4 and 1.

8. shamil98

correct.

9. swissgirl

Correct

10. shamil98

so, in (x+b)(x-b)=0 form it would be?

11. swissgirl

So basically then we replace -3x with -4x +1x

12. swissgirl

So our equation would look as follows \(x^2-4x+1x-4\)

13. shamil98

(x-4)(x+1) = 0 after you put it in that form x - 4 = 0 and x + 1 = 0 solve for x to get your solutions.

14. swissgirl

Then we group the first 2 terms and teh last 2 terms \( (x^2-4x)+(x-4)=0

15. swissgirl

\( (x^2-4x)+(x-4)=0\)

16. swissgirl

Then we factor out from each bracket x(x-4)+1(x-4)=0

17. shamil98

You made a mistake I believe.. @swissgirl

18. swissgirl

At which point?

19. shamil98

Well, she is asking how to find the solution, I have no idea what you are showing.. the original equation is x^2 - 3x - 4. factored out (x-4)(x+1)= 0 x = -1 x =4

20. shamil98

x^2 - 4x + x -4 can just be simplified to x^2 -3x - 4 .....

21. swissgirl

Yes but I am just demonstrating how you factored it out This is the typical way it is taught in school and when it becomes more challenging then it is imperative that you write it out in this fashion

22. swissgirl

@Katelynmorris which method are you familiar with?

23. shamil98

It looks more complicated with your method x^2 -3x -4 you know that the values are 1 and - 4. just put that like this (x-4)(x+1) = 0

24. Katelynmorris

I am lost after the x^2-4x+1x-4=0..Solving by factoring

25. swissgirl

But @shamil98 it works this time but what happens if the equation was \(3x^2-3x-4=0\) ?

26. Katelynmorris

Ok so after the (x-4)(x+1)=0 that gives me x how?

27. LolaTorezz2011

listen to sham, he got da plan @_@

28. shamil98

(x-4)(x+1)=0 you put x-4=0 and x+1=0 to get your solutions .

29. LolaTorezz2011

@Katelynmorris just look at daht smart score of his @_@ YO SWISS, DONT BE CHEESY <3 I loe u, but let L do his Justice <3

30. shamil98

3x2−3x−4=0 swiss, i would use the quadratic formula. instead of trying to factor it.

31. swissgirl

You can use whtvr it makes no diff as long as you get your answer

32. shamil98

Your method is much more complicated than it needs to be, just make it simple..

33. swissgirl

The only reason why I was showing him that method since that is the method taught in schools

34. swissgirl

Plus your method wont work for complicated equations trust me kid

35. Katelynmorris

Ok so x= 4, -1?

36. shamil98

Yes, those are your solutions.

37. Katelynmorris

Thanks.

38. LolaTorezz2011

as a drunk person on peaches, let me tell u somethin swiss cheese, sham aint no kid, he be Justice @_@

39. LolaTorezz2011

don't make me get my peaches loe <3 @Katelynmorris listen to sham, hes been doin dis for years @_@ just look at daht bronze 76 he got @_@

40. BulletWithButterflyWings

every time you type @_@ you tag whoever that is lol

41. LolaTorezz2011

LAWL XD

42. LolaTorezz2011

OMG THEY ACTUALLY EXCIST o-o

43. LolaTorezz2011

I have been using that face for so many times like this.........they will witness the spam of there lives when they come back XD

44. BulletWithButterflyWings

stalking profile now

45. LolaTorezz2011

XD