What is the center of a circle whose equation is x2 + y2 + 4x – 8y + 11 = 0? (–2, 4)
(–4, 8)
(2, –4)
(4, –8)

Step-by-step explanation:

eq. of circle is x²+y²+2gx+2fy+c=0

center=(-g,-k)

given eq. is x²+y²+4x-8y+11=0

comparing

2gx=4x

g=2

2fy=-8y

f=-4

center=(-2,4)

81/100

Step-by-step explanation:

Here's how to convert 0.81 to a fraction...

There is not much that can be done to figure out how to write 0.81 as a fraction, except to literally use what the decimal portion of your number, the .81, means.

Since there are 2 digits in 81, the very last digit is the "100th" decimal place.

So we can just say that .81 is the same as 81/100.

So your final answer is: 0.81 can be written as the fraction 81/100