Hi, Yes! Your factoring completely was good work
200w^2+640wg+512g^2
8(25w^2 + 80wg + 64g^2)
8(5w + 8g)(5w + 8g) = 8(5w + 8g)^2
May check Your factoring using the FOIL Method
F First terms 25w^2
O Outside terms 40wg
I Inside terms 40wg
L Last terms 64g^2