Question 178902
You can factor both denominators,
{{{3y/(4y-20)+9y/(6y-30)=3y/(4(y-5))+9y/(6(y-5))}}}
{{{3y/(4y-20)+9y/(6y-30)=(3y/4)/(y-5)+(9y/6)/(y-5)}}}
Since they have the same denominator, we can just add numerators,
{{{3y/(4y-20)+9y/(6y-30)=((3y/4)+(9y/6))/(y-5)}}}
Let's focus on the numerator only and simplify it,
{{{(3y/4)+(9y/6)=(3/3)(3y/4)+(2/2)(9y/6)}}}
{{{(3y/4)+(9y/6)=(9y/12)+(18y/12)}}}
{{{(3y/4)+(9y/6)=(9y+18y)/12)}}}
{{{(3y/4)+(9y/6)=(27y)/12)}}}
{{{(3y/4)+(9y/6)=(9y)/4)}}}
Now we replace that in the numerator,
{{{3y/(4y-20)+9y/(6y-30)=((3y/4)+(9y/6))/(y-5)}}}
{{{3y/(4y-20)+9y/(6y-30)=(9y/4)/(y-5)}}}
{{{3y/(4y-20)+9y/(6y-30)=9y/(4(y-5))}}}