## anonymous one year ago What are the solutions to the quadratic equation 5x2 + 60x = 0? x = 0 and x = −12 x = 0 and x = 12 x = 5 and x = −12 x = 5 and x = 12

1. taramgrant0543664

Do you have an idea on how to do this?

2. anonymous

I think I do somewhat

3. UsukiDoll

factor out the like terms for $5x^2+60x=0$

4. anonymous

Aren't I supposed to find what 5^2 and 60 have in common or something like that or I am mistaken ._.

5. UsukiDoll

yeah.... you are supposed to find what they have in common and yank em out.

6. taramgrant0543664

Well in order to get 0 on the right we know that x=0 in one case because substituting 0 in we will get 0 on the left

7. taramgrant0543664

To find the second number you have to factor out what you can so what can you factor out?

8. UsukiDoll

let's split this up for a sec $5x^2+(5)(12)x=0$ ok what number do they have in common and what variable do they have in common?

9. anonymous

They have 5 and 12 in common.... 5 and 12 have..... 3 in common I guess.... since 3 times 3 is 12 and 3 +2 = 5

10. taramgrant0543664

They both have 5x in common so you can factor that out

11. taramgrant0543664

So 5x(x+12)=0

12. UsukiDoll

how is 3 x 3 12? 3 x 3 = 9

13. anonymous

I meant 3 times 4 sorry

14. taramgrant0543664

To get the inside the brackets equal to 0 how do you get that?

15. UsukiDoll

well 12 x 5 = 60. when I split it up we have a 5 for the number in common and x for the variable in common so 5x gets yanked out and we're left with 5x(x+12)=0 now we solve for x for these two cases 5x = 0 and x +12 = 0

16. anonymous

By subtracting because we want less?

17. pooja195

Solve both for x

18. anonymous

x = 0 its so simple ._.

19. UsukiDoll

@pooja195 yes solve both equations for x

20. pooja195

5x = 0 (divide) x +12 = 0 (sibtract)

21. taramgrant0543664

(X+12)=0 you want some number to be negative so it equals 0

22. UsukiDoll

we want x by itself for x+12=0 so we subtract both sides by 12

23. anonymous

The answer is still zero since 0 minus 12 is 12 and 12 divided by 0 is ZERO so both answers are Zero :D

24. UsukiDoll

omg I am facepalming over this.

25. UsukiDoll

there are two solutions of x.

26. UsukiDoll

we got x = 0 for 5x=0 now solve x+12 = 0 by subtracting 12 on both sides.

27. anonymous

28. anonymous

I DID!

29. pooja195

0-12?

30. taramgrant0543664

X+12=0 x+12-12=0-12

31. anonymous

GOD ITS LIKE 6th grade ALGEBRA! 12 minus zero is 12

32. taramgrant0543664

Zero minus twelve not twelve minus zero

33. anonymous

Well Negative 12

34. UsukiDoll

thank you @taramgrant0543664

35. anonymous

But it is still 12

36. anonymous

Just on the left side XD

37. taramgrant0543664

Zero minus twelve is negative twelve

38. anonymous

I just said that ._.

39. UsukiDoll

5x(x+12) = 0 5x = 0 divide 5 on both sides and we have x = 0 x+12 = 0 -12 -12 x = -12

40. taramgrant0543664

It's not twelve it's negative twelve

41. anonymous

Well sorry! The answer is A i finally finished the test thanks and sorry for being a freaking idiot..... its just late and I have been doing work all day and by now my head is just on fire ._. I am going to bed good night

42. anonymous

@UsukiDoll Sarcasm is one of my many flaws its an aspect of my personality I have to fix...... I am very sorry if I was a jerk or I offended you in any way thanks for the help and patients both you and @taramgrant0543664

43. UsukiDoll

ah... that's ok. I take meds in real life or get high blood pressure so I type some crazy stuff sometimes too. XD

44. mathstudent55

$$\Large 5x^2 + 60x=0$$ Factor out the common factor 5x: $$\Large \color{red}{5x} \cdot x + 12 \cdot \color{red}{5x} = 0$$ $$\Large 5x(x + 12) = 0$$ Divide both sides by 5: $$\Large x(x + 12) = 0$$ Set both factors equal to 0: $$\Large x = 0$$ or $$\Large x + 12 = 0$$ Solve both equations for x: $$\Large x = 0$$ or $$\Large x = -12$$

45. anonymous

lol ok

46. UsukiDoll

meow ^.^

47. anonymous

Oh and I got an 89% in the test! XD

48. anonymous

So double thanks now good night and bye

Find more explanations on OpenStudy