Question 949164
No.
Look at the right hand term.
{{{6xy^3-6xy^3=0}}}
When you subtract zero from any term, you get that term.
{{{(xy^3+3x^3y)-(6xy^3-6xy^3)=(xy^3+3x^3y)-(0)}}}
{{{(xy^3+3x^3y)-(6xy^3-6xy^3)=highlight(xy^3+3x^3y)}}}