Question

1/7-3(3/7n-2/7) I need help solving this problem...

Answer 1

The answer is 1/7n + 32/21 

Answer 2

So we have 
$\dfrac{1}{7}-3( \dfrac{3}{7n}- \dfrac{2}{7})$

The first step is to distribute the –3

$\dfrac{1}{7}+( \dfrac{-3*3}{7n}- \dfrac{-3*2}{7})$

Next, we simplify within the parentheses. In order to do this, we must have a common denominator. 

$\dfrac{1}{7}+( \dfrac{-9}{7n}- \dfrac{-6}{7}* \dfrac{n}{n} ) \\ \\ \\ \\ \dfrac{1}{7}+( \dfrac{-9}{7n}- \dfrac{-6n}{7n} ) \\ \\ \\ \\ \dfrac{1}{7}+ \dfrac{-9+6n}{7n}$

Then, we find a common denominator again and simplify.

$\dfrac{1}{7}* \dfrac{n}{n} + \dfrac{-9+6n}{7n} \\ \\ \\ \\ \dfrac{n-9+6n}{7n} \\ \\ \\ \\ \dfrac{7n-9}{7n}$

And we're done. While it may be tempting to try to cancel 7n, this is not actually allowed. Try substituting in a non-zero number for n and you'll see why.