Question 6173
Start with {{{5X^2*Y^2*Z^3-X^2*Y}}}

them REPLACE X with -2, Y with 5, Z with -1:

{{{ 5*(-2)^2*5^2*(-1)^3 - (-2)^2*5}}}

*[invoke explain_simplification "5*(-2)^2*5^2*(-1)^3 - (-2)^2*5"]