Question 588068
<pre>
{{{(15y+5)/(-21y-7)}}}

Factor 5 out of the numerator:

{{{(5(3y+1))/(-21y-7)}}}

Factor -7 out of the denominator

{{{(5(3y+1))/(-7(3y+1))}}}

Cancel the (3y+1)'s

{{{(5(cross(3y+1)))/(-7(cross(3y+1)))}}}

{{{5/(-7)}}}

{{{-5/7}}}

Edwin</pre>