AriannaA 2 years ago Find the values of x in the following equation: |9x + 9| = 18

1. skullpatrol

Do you want learn how to work with absolute values?

2. AriannaA

I just don't get it. >.<

3. skullpatrol

Let me start with the definition: absolute value: The positive number of any pair of opposite nonzero real numbers is the absolute value of each number in the pair.

4. skullpatrol

This definition is stating that the absolute value is a POSITIVE number.

5. skullpatrol

Let me show you with your question how to apply this definition.

6. AriannaA

Ah. I see. Thank you very much for helping me. I appreciate it. Continue, please. :3

7. skullpatrol

|dw:1361364277172:dw|

8. viniterranova
9. skullpatrol

Can you solve the equation \$\$9x +9 =18\$\$

10. skullpatrol

Similarly we use the same argument for the opposite of 18 or -18....

11. AriannaA

With 9x + 9 = 18, the "x" stands for 3, right? :o

12. skullpatrol

does 9(3) + 9 =?= 18

13. skullpatrol

27 + 9 =36 =/=18

14. ParthKohli

Think of it this way:|dw:1361365016230:dw|

15. AriannaA

So... The answer is 18x?

16. skullpatrol

No, try and solve for x in \$\$9x + 9 = 18\$\$

17. skullpatrol

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18. skullpatrol

@AriannaA Do you follow what I just did?

19. AriannaA

I'm really confused now.

20. skullpatrol

Concentrate on ONLY solving the equation. Subtract 9 from both sides, then divide both sides by 9

21. skullpatrol

|dw:1361365682344:dw|

22. viniterranova

|dw:1361365739823:dw|

23. coreymacg

What you have to do Arianna is get X by itself 9x + 9=18 To get this by itself you have to remove things from around the x. 9x + 9 = 18 What ever you do to the left side of the = sign you have to do to the right let em show you 9x + 9 = 18 - 9 - 9 --------------- 9x + 0= 9 /9 /9 /=divide 1x + 0 = 1 ------------- We read this as x = 1 so the answer is x = 1 now plug 1 into x 9(1) + 9 = 19 9 + 9 = 18 18=18 this is true

24. viniterranova

9x+9=18 and 9x+9=-18 this is taken from definition of the absolute value.

25. AriannaA

So 18=18 is the answer? I'm sorry if I'm being difficult.

26. coreymacg

x = 1 is the answer

27. coreymacg

you have to solve for x because x is the only thing we do not know here.

28. AriannaA

Oh. I see. :o

29. coreymacg

Do you understand how I got this answer?

30. skullpatrol

Do you want me to continue?

31. skullpatrol

@AriannaA Are you still there?