## Algebra: A Combined Approach (4th Edition)

$7xy^2$
$7x^3y^3 = 7 \times x^3 \times y^3$ $-21x^2y^2 = -1 \times 7 \times 3 \times x^2 \times y^2$ $14xy^4 = 7 \times 2 \times x \times y^4$ So the Greatest Common Factor is $7xy^2$