# How do you simplify  xy^3(1 - xy + x^2)?

$x {y}^{3} - {x}^{2} {y}^{4} + {x}^{3} {y}^{3}$
$x {y}^{3} \left(1 - x y + {x}^{2}\right)$
$= x {y}^{3} \cdot 1 + x {y}^{3} \cdot - x y + x {y}^{3} \cdot {x}^{2}$
$= x {y}^{3} - {x}^{2} {y}^{4} + {x}^{3} {y}^{3}$