Intermediate Algebra (6th Edition)

$12x^{3}y+8x+8$
We are asked to add $(7x^{3}y-4xy+8)+(5x^{3}y+4xy+8x)$. We can combine like terms to add these polynomials together. $(7x^{3}y+5x^{3}y)+(-4xy+4xy)+8x+8=12x^{3}y+8x+8$