Answer
$2x^4y^2+11x^3y-y-8x$
Work Step by Step
Consider the given polynomial
$(5x^4y^2+6x^3y-7y)-(3x^4y^2-5x^3y-6y+8x)$
Need to drop the parentheses and will have to change the sign of each term of the second polynomial because of the presence of the negative outside.
Thus,
$(5x^4y^2+6x^3y-7y)-(3x^4y^2-5x^3y-6y+8x)=5x^4y^2+6x^3y-7y-3x^4y^2+5x^3y+6y-8x$
or, $=5x^4y^2-3x^4y^2+6x^3y+5x^3y-y-8x$
or, $=2x^4y^2+11x^3y-y-8x$
