Convert to cylindrical coordinates:



Then
is the set of points
such that
,
, and
or
.
Now

The answer is no solution
x,y = 9,5 is the answer no it not
Table:
<span>Years (x) 1 2 3 4 5 6
Money (y) (hundreds of dollars) 15 30 45 60 75 90
</span>
y = 15(x)
y = 15(9)
y = 135 hundreds of dollars
<span>y = 15x, in 9 years he will have saved $13,500</span>