## Solmyr Group Title What are the solutions of x2 + 5x − 24 = 0? Show all work for full credit. one year ago one year ago

do it by factorizing...

2. hartnn

hint : split the middle term as 8x-3x

break 5x in two terms.

8x-3x

5. Solmyr

would it be −b±/b^2 - 4ac ------------- 2a

6. hartnn

thats using Quadratic formula...are u asked to use that ? if not factorizing will be better approach

7. Solmyr

8. hartnn

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

9. hartnn

so, first tell me what u get for a,b,c.

10. Solmyr

a=x^2 b=5 c=24

11. hartnn

no, 'a' is the co-efficient of x^2 here u have 1x^2 so a=.... ?

12. Solmyr

1^2

13. hartnn

|dw:1356626845466:dw|

14. Solmyr

a=1 b=5 c=24

15. hartnn

are u sure about the value of 'c' ?

16. Solmyr

-24

17. hartnn

correct, now just plug in the values of a,b,c in that quadratic formula

18. Solmyr

−b±/b^2 - 4ac ------------- 2a -5 +/5^2 - 4 * 1 * 24 ------------------ 2 -5 +/ 25 - 96 ----------- 2

19. Solmyr

-5 -/5^2 - 4 * 1 * 24 ------------------ 2 -5 -/ 25 - 96 ----------- 2

20. hartnn

remember that c=-24 so $$b^2-4ac = 25-4(1)(-24) = 25+96=...?$$

21. Solmyr

i cant believe i keep messing that up

22. hartnn

everything else was correct.

23. Solmyr

121

24. hartnn

yes, and $$\sqrt{121}=..?$$

25. Solmyr

11 SR

26. Solmyr

-5 + 11= 6 -- = 3 2

27. hartnn

yes, and (-5-11)/2 =... ?

28. hartnn

?

29. Solmyr

-8

30. hartnn

thats correct, so 2 roots are 3 and -8.

31. Solmyr

ok thank u for all ur help

32. hartnn

welcome ^_^