## DF001 one year ago How can I solve this problem in LCD method?

1. DF001

|dw:1441761645186:dw|

2. DF001

I know the first step is to flip the second fraction but I am lost after that

3. DF001

|dw:1441761884045:dw|

4. anonymous

It looks like they want a different method. one denominator is 9 the other is 3x, so the LCD will be 9x.

5. anonymous

multiply by 9x/9x

6. anonymous

|dw:1441761936372:dw|

7. DF001

How do you figure that the lcd is 9x

8. anonymous

then cancel|dw:1441761977491:dw|

9. DF001

can you also show me the alternative method that they may want me to use?

10. anonymous

lcd is 9x because you need one part of each thing in the denominators. so you need 3x and 9. Since 3 is a factor of both, it's 9x

11. anonymous

This is the alternative method where you multiply by 9x/9x on top and bottom.

12. anonymous

the other one is where you flip. did you want to go through this both ways?

13. DF001

im sorry i stepped out for a second I want to use the alternative way, please show me

14. anonymous

the lcd is 9x, so you have to multiply both fractions by it and then the denominators will cancel |dw:1441762561073:dw|

15. anonymous

understand?

16. DF001

I think I do now but a little kinks i need to figure out myself :)

17. DF001

ill work on the question with your steps for a bit, ill try to get back to this after im done

18. DF001

wait but, if i flip the other fraction when multiplying, doesnt the lcd change?

19. anonymous

ok. the only thing left is to factor the new denominator (3x - 18) to 3(x - 6) then you can cancel more|dw:1441762727663:dw|

20. DF001

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21. anonymous

if you're multiplying you don't use the lcd, you factor and cancel

22. DF001

oh, do i factor 3x-18

23. anonymous

|dw:1441762803117:dw|

24. anonymous

yes, same solution with both methods

25. DF001

ah i see now