Question 704635
<pre>
I'll assume it's 

{{{expr(7/9)w}}}{{{""=""}}}{{{7}}}

Since there is a fraction on the left side, make the
right side a fraction too by putting a 1 under it:

{{{expr(7/9)w}}}{{{""=""}}}{{{7/1}}}

What you want is w or 1w, not {{{expr(7/9)w}}}.

So you have to multply {{{7/9}}} by its reciprocal {{{9/7}}}
to make {{{7/9}}} into 1.

But if you multiply one side by {{{9/7}}} you have to
multiply the other side by {{{9/7}}} too.

{{{expr(9/7)*expr(7/9)w}}}{{{""=""}}}{{{expr(9/7)*expr(7/1)}}}

Cancel the 9's on the left:

{{{expr(cross(9)/7)*expr(7/cross(9))w}}}{{{""=""}}}{{{expr(9/7)*expr(7/1)}}}

Cancel the 7's on the left AND the right:

{{{expr(cross(9)/cross(7))*expr(cross(7)/cross(9))w}}}{{{""=""}}}{{{expr(9/cross(7))*expr(cross(7)/1)}}}

Now all that's left is

{{{x}}}{{{""=""}}}{{{9}}}

Edwin</pre>