Question 112561
{{{a^2 - 3a + ay - 3y}}}
{{{a^2 - (3 - y)a - 3y}}}
I just try likely combinations and see if they work
{{{(a - 3)(a + y)}}}
Now I expand this
{{{a^2 - 3a + ay - 3y}}}
That's the original equation, so I have factored it