## anonymous one year ago NEED HELP! Solve for n: 21k -3n + 9p > 3p + 12 A. n > 2p + 7k - 4 B. n < 2p + 7k - 4 C. n > -4p - 7k + 4 D. n < -4p - 7k + 4

1. dan815

solve equations with inequality instead of equal sign is very similiar, only have to worry about sign changing operations

2. anonymous

i'm lost sorry

3. dan815

do you know how to solve this 21k -3n + 9p = 3p + 12

4. dan815

if there is an equal sign, how do you solve for n?

5. anonymous

first do i add something?

6. dan815

|dw:1434743334964:dw|

7. dan815

only difference is if u multiply both of them by -1 , then what was greater will be more negative

8. dan815

|dw:1434743494515:dw|

9. dan815

|dw:1434743610549:dw|

10. dan815

|dw:1434743716649:dw|

11. dan815

|dw:1434743745158:dw|

12. dan815

see how -1 works with the number line now?

13. anonymous

yes but now how do i start solving?

14. dan815

the same way you solve normal equations, only remember how multiplication by negative number changes it

15. dan815

21k -3n + 9p > 3p + 12 isolate for n

16. dan815

solve for n like you do a normal equation, keep track of the number of times you multiply by a negative number

17. dan815

if the number of times you multiply by a negative number is odd, then you flip sign else u keep the sign oriented same way

18. anonymous

can i put 3p and 12 together?

19. dan815

what do u mean?

20. anonymous

like terms

21. dan815

ya, u have to have n all by itself

22. dan815

21k -3n + 9p > 3p + 12 okay so we saw how adding and subtracting will keep the inequality, as everything just gets shifted left or right

23. dan815

|dw:1434744122685:dw|

24. dan815

|dw:1434744155894:dw|

25. dan815

21k -3n + 9p > 3p + 12 so subtract 21k from both side and 9p

26. dan815

21k -3n + 9p > 3p + 12 -3n > 3p+12 -21k -9p

27. dan815

what do you think we should to now?

28. dan815

u can go the other way too u can add 3n to both sides as well as subtract 3p and 12 from both sides 21k -3n + 9p > 3p + 12 21k + 9p -3p - 12 > 3n notice in this case it automatically takes care of the sign flip

29. anonymous

can you help me with another one? like walk through w me

30. dan815

yep, did u finish this one though, what did u get?