SOLUTION: 3n over 4 - 1 over 3 = 2n-1 over 6 multiplied each fraction by 12 and cancelled denominators to get whole numbers then got n=2 over 5 but when I checked answer and substituted n

Algebra ->  Equations -> SOLUTION: 3n over 4 - 1 over 3 = 2n-1 over 6 multiplied each fraction by 12 and cancelled denominators to get whole numbers then got n=2 over 5 but when I checked answer and substituted n      Log On


   

Question 164774: 3n over 4 - 1 over 3 = 2n-1 over 6
multiplied each fraction by 12 and cancelled denominators to get whole numbers
then got n=2 over 5
but when I checked answer and substituted n for 2 over 5, i didnt get an equal answer
Found 2 solutions by Edwin McCravy, Mathtut:
Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!
3n over 4 - 1 over 3 = 2n-1 over 6
multiplied each fraction by 12 and cancelled denominators to get whole numbers
then got n=2 over 5
but when I checked answer and substituted n for 2 over 5, i didnt get an equal answer


You solve it right but checked it wrong.

3n%2F4-1%2F3=%282n-1%29%2F6

Put parentheses around every term

%283n%2F4%29-%281%2F3%29=%28%282n-1%29%2F6%29

Multiply every term by %2812%2F1%29


%2812%2F1%29%283n%2F4%29-%2812%2F1%29%281%2F3%29=%2812%2F1%29%28%282n-1%29%2F6%29

Cancel:

  3           4          2



9n-4=2%282n-1%29

9n-4=4n-2

5n=2

n=2%2F5

Checking:

%283n%2F4%29-%281%2F3%29=%28%282n-1%29%2F6%29

%283%282%2F5%29%2F4%29-%281%2F3%29=%28%282%282%2F5%29-1%29%2F6%29

%28%286%2F5%29%2F4%29-%281%2F3%29=%28%284%2F5-1%29%2F6%29%29

%286%2F5%29%281%2F4%29-%281%2F3%29=%28%284%2F5-5%2F5%29%2F6%29%29

  3
%28cross%286%29%2F5%29%281%2Fcross%284%29%29-%281%2F3%29=%28%28-1%2F5%29%2F6%29%29
       2         

%283%2F10%29-%281%2F3%29=%28-1%2F5%29%281%2F6%29

3%2F10+-+1%2F3=-1%2F30

9%2F30+-+10%2F30+=+-1%2F30
-1%2F30+=+-1%2F30

Edwin

Answer by Mathtut(3670) About Me  (Show Source):
You can put this solution on YOUR website!
your answer is correct your probably multiplying in error when your plugging in ... for instance it is easy to see 3(2/5) as 3 and 2 fifths and thus call it 17/5 when substituted properly it works.... with -2/5 = -2/5