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## anonymous one year ago Solve 3x2 + 6x + 15 = 0

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1. anonymous

@mathstudent55

2. anonymous

@welshfella

3. anonymous

standered form

4. anonymous

no using the quad. equation

5. anonymous

oh x=−1±2i

6. welshfella

divide through by 3;- 3(x^2+2x+5) = 0

7. welshfella

@jamese please don't give direct answers

8. anonymous

Thanks:)

9. welshfella

this won't factor so you can use the quadratic formula

10. anonymous

I did. and then I got -6 + or negativd radical 144

11. anonymous

then you simplify|dw:1437503232700:dw|

12. welshfella

it would be simpler to solve what in the parentheses x^2 + 2x + 5 = 0

13. anonymous

Then i got -1 plus/neg 2i

14. anonymous

ight but i cant help it i like it

15. welshfella

|dw:1437503348625:dw|

16. welshfella

@jamest - you risk being supended

17. anonymous

then for rad. 20 you get 4, 5 which can be simplified to 2 radical 5

18. welshfella

|dw:1437503520235:dw|

19. welshfella

now one more simplification and you have it

20. mathstudent55

$$3x2 + 6x + 15 = 0$$ $$x^2 + 2x + 5 = 0$$ $$x = \dfrac{-b \pm \sqrt {b^2 - 4ac}}{2a}$$ $$x = \dfrac{-2 \pm \sqrt {2^2 - 4(1)(5)}}{2(1)}$$ $$x = \dfrac{-2 \pm \sqrt {4 - 20}}{2}$$ $$x = \dfrac{-2 \pm \sqrt {- 16}}{2}$$ $$x = \dfrac{-2 \pm 4i}{2}$$ $$x = -1 \pm 2i$$

21. anonymous

ight thx for lettin me know

22. anonymous

Thanks:) !

23. welshfella

oops - sorry - i goofed up on the i on!

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