Question

What is the center and radius of the circle with the given equation?
x^2+y^2+8x-4y=-11

Answer 1

x² - 8x (leave a gap) + y² + 4y (leave a gap) = -11
to fill in the gaps, you complete the square
divide coefficient of x by 2 and then square it.
First gap: (8/2)² = 16
Second gap (4/2)² = 4
You have to add these numbers to both sides.
x² - 8x + 16 + y² + 4y + 4 = -11 + 16 + 4
Now factor the expressions on the left and add the numbers on the right.
(x - 4)² + (y + 2)² = 9

The center is (4, -2) and the radius is SQRT(9) = 3.

Answer 2

There you goo :)

Answer 3

Can i get a medal

Answer 4

thank you!