Question 182081
{{{(15x^3y^2-8x^2y+7xy^2)-(3x^3y^2+3x^2y-4xy^2)}}}

1. Remove the first set of parentheses (unnecessary) and distribute the minus sign:
{{{15x^3y^2 - 8x^2y + 7xy^2 - 3x^3y^2 - 3x^2y + 4xy^2)}}}

2. Rearrange the terms so like terms are next to one another:
{{{15x^3y^2 - 3x^3y^2 - 8x^2y - 3x^2y + 7xy^2 + 4xy^2)}}}

3. Add and subtract like terms (parentheses below are for emphasis):
{{{(15x^3y^2 - 3x^3y^2) - (8x^2y - 3x^2y) + (7xy^2 + 4xy^2))}}}
{{{12x^3y^2 - (8x^2y - 3x^2y) + (7xy^2 + 4xy^2)}}}
{{{12x^3y^2 - 5x^2y + (7xy^2 + 4xy^2)}}}
{{{12x^3y^2 - 5x^2y + 11xy^2}}}
The last equation is your answer.