Answer:
{x,y} = {-1,-9}
Step-by-step explanation:
For any equation,

assume solution of a form, 
Which leads to,

Simplify to,

Then find solutions,

For non repeated real root y, we have a form of,

Following up,
For two non repeated complex roots
where,

and,
the general solution has a form of,

Or in this case,

Now we just refine and get,

Hope this helps.
r3t40
Answer:
11th revision
Step-by-step explanation:
The first revision is in 2018, and for each 3 years there is a new revision.
From 2018 to 2048, there are 30 years.
So to find how many revisions there are, we can divide the 30 years by the period of 3 years:
Number of revisions = total period / period per revision = 30 / 3 = 10 revisions.
As the year 2018 also has a revision, we have 10 + 1 = 11 total revisions.
So in 2048 there will be the 11th revision.