Answer: -3
The coefficient is the number that is getting multiplied by the variable
By letting

we get derivatives


a) Substitute these into the differential equation. After a lot of simplification, the equation reduces to

Examine the lowest degree term
, which gives rise to the indicial equation,

with roots at r = 0 and r = 4/5.
b) The recurrence for the coefficients
is

so that with r = 4/5, the coefficients are governed by

c) Starting with
, we find


so that the first three terms of the solution are

The answer is 1188.
Hope it helped :)
Move x to the right side, so we could get y=-3-x.
If you didn't have a calculator, go to https://www.desmos.com/calculator and graph it. The rest is your work.