Question

(2 ,-5 ,0 ,5 ,6) is the coefficient form of the polynomial represent in index form

Answer 1

I hope so it is right.

Answer 2

$2 {x}^{4} - 5 {x}^{3} + 0 {x}^{2} + 5x + 6 \\ \\ = 2 {x}^{4} + 5 {x}^{3} + 5x + 6$
hope this helps