First we should find the general term of
Now since they told us that the coefficient of

is 0, we can find

by finding the coefficient of

in terms of

.
Since the general term is being multiplied by
)
we multiply the general term by each of the values in the bracket, then find the coefficients of

in both cases, then we add them together to find the actual coefficient of

.

Since we need to find the coefficient of

we let

.

Since we need to find the coefficient of

we let

.