Answer
$x^5/32 + (5 x^4)/8 + 5 x^3 + 20 x^2 + 40 x + 32$
Work Step by Step
The coefficients of the polynomial expression will simply be the pascal's triangle number row corresponding to the power. Also the power's of x will start with the power and go down. The constant or y term will go up starting with to the power 0. Also if there is a coefficient of either term (like 4x instead of x) simply consider the coefficient as part of the whole term and expand afterwards