Question 128178
To find the difference of two expressions subtract one from the other:
{{{(2x^2 + 4xy - 3) - (x^2 - 2xy - 4)}}}
Multiply the second parentheses by the negative:
{{{2x^2 + 4xy - 3 - x^2 + 2xy - 4}}} 
Combine like terms to find your answer:
{{{x^2 + 6xy - 7}}}