Question 21520
Factor: {{{15+3y-15x^2-x^2y}}}
The best we can do on this is factor by grouping:

{{{(15+3y) - (15x^2+x^2y)}}} Factor 3 from the fist group and x^2 from the second group.
{{{3(5+y) - x^2(15+y)}}} and this could be arranged as:
{{{-(x^2(y+15) - 3(y+5))}}}