What am i doing wrong?

[bobisaka]

Tried another way without getting rid of fractions, still wrong answer.
This time I have cleared the fractions and still get wrong answer.

1/2(k-3)=1/3(k+16)

1/2k-3/2= 1/3k+16/3

6(3/6 k-9/6)=6(2/6 k+48/6)

18/6 k-54/6=12/6 k+288/6

3k-9=2k+48

3k-2k-9=2k-2k+48

k-9=48

k=57

CHECK

1/2(57-3)=1/3(57+16)

23.5-1.5=19+5.3

22 = 24.3

Help appreciated.

 

[Coefficient]

Tried another way without getting rid of fractions, still wrong answer.
This time I have cleared the fractions and still get wrong answer.

1/2(k-3)=1/3(k+16)

Does this mean (1/2)*(k-3) = (1/3)(k+16) or 1/(2*(k-3)) = 1/(3*(k+16)) ??

 

[pka]

\(\displaystyle \frac{1}{2}(k-3)=\frac{1}{3}(k+16) \\3(k-3)=2(k+16)\\3k-9=2k+32\\k=41\)

 

[bobisaka]

Can you tell me how you got to you second step?

How did you get 3(k-3) = 2k+16

\(\displaystyle \frac{1}{2}(k-3)=\frac{1}{3}(k+16) \\3(k-3)=2(k+16)\\3k-9=2k+32\\k=41\)

 

[Coefficient]

Can you tell me how you got to you second step?

How did you get 3(k-3) = 2k+16

he multiplied both sides by 6 to get rid of the fractions

 

[bobisaka]

ah yeah, i see i did that in my equations but i must have messed up the right side of it..

6(3/6 k-9/6)=6(2/6 k+48/6)

18/6 k-54/6=12/6 k+288/6

he multiplied both sides by 6 to get rid of the fractions

 

[JeffM]

Tried another way without getting rid of fractions, still wrong answer.
This time I have cleared the fractions and still get wrong answer.

1/2(k-3)=1/3(k+16)

1/2k-3/2= 1/3k+16/3

6(3/6 k-9/6)=6(2/6 k+48/6)

18/6 k-54/6=12/6 k+288/6

The three steps above are unnecessary. Any unnecessary step gives an extra chance of making an error. Clear fractions right away.

[MATH]\frac{1}{2} * (k-3) = \frac{1}{3} * (k+16) \implies[/MATH]
[MATH](2 * 3) * \frac{1}{2} * (k - 3) = (2 * 3) * \frac{1}{3} * (k + 16) \implies 3(k - 3) = 2(k + 16) \implies[/MATH]
[MATH]3k - 9 = 2k + 32[/MATH] not 3k-9=2k+48

 

[bobisaka]

Okay i understand. Now i need to rewire my brain a bit to do it more efficiently.

 

[pka]

Okay i understand. Now i need to rewire my brain a bit to do it more efficiently.

NO! no rewiring necessary. Just go back and practice arithmetic.

 

[bobisaka]

NO! no re wiring necessary. Just go back and practice arithmetic.

Haha got it.

 

[Steven G]

6(3/6 k-9/6)=6(2/6 k+48/6)
18/6 k-54/6=12/6 k+288/6

You are multiply both sides by 6 to clear the fraction. There is no need to multiply by 6 (as in 6*48) before doing the division. The 6's cancel out.

How would you simplify \(\displaystyle 7134*\dfrac{12}{7134}?\). Would you multiply 7134 by 12? You could but then you would have to reduce and in the end you would get back to 12.
Think about this. Suppose you are doing a long calculation with your calculator. You have 12 in your calculator and then by accident divided by 7134. Now your calculator shows the result of 12/7134. How would you undo that division? The answer is you multiply back by 7134 and you will get 12 as the answer.