Answer: x^2+y^2+2x-18y+18=0 in standard form is (x+1)^2+(y-9)^2=64
Answer:
B) 4
Step-by-step explanation:
We can solve this by observing some pattern.
The powers ending in 4 as unit digit are:

The exponents form the sequence:
2,6,10,14,20,...
We need to check if 62 belongs to this sequence.
This is an arithmetic sequence with a common difference of 4 and a first term of 2.
The explicit formula is

We equate this to 62 and solve for n.

Since n is a natural number, 62 belongs to the sequence.
Hence

will have a unit digit of 4.

First compute the first-order partial derivatives and find the critical points.


Both first order derivatives vanish at

.
Computing the Hessian, we get

We have

, which means

is an extremum of

. Since

, this extremum is a local maximum of

with a value of 21.