2x(x-y)+y(x-y)
2x(x+y)+(x+y)

2x² - y² - xy

2x² + 2xy + x + y

Step-by-step explanation:

2x(x - y) + y(x - y) =

2x² - 2xy + xy - y² =

2x² - y² - xy

2x(x + y) + (x + y) =

2x² + 2xy + x + y

answer: there are 453.592 grams in a pound.

step-by-step explanation:

descending order means to order the polynomials from the term with the largest exponent to the term with the smallest exponent.  

therefore, the correct answer is d.