The equation 2x2 + 2y2 – 8x – 12y + 16 = 0 defines a circle. Which of these shows a correct step for determining the center and radius of this circle? Choose all that are correct.
(2x2 – 8x + 16) + (2y2 – 12y+36) = -16+ 36
(x - 4)2 + (y - 9)2 = 5
(x2 - 4x +4) + (y2 - 6y +9) = -8 +13
o 22 + y2 – 4x - 6y= -16
(x - 2)2 + (y - 3)2 = 5

angle efh= angle egh

your answer is  

d.

196.5 m2

step-by-step explanation:

x^2 + 81

we can factor this using difference of square binomials.

rewrite the equation:

x^2 - (-81)

factor:

(a^2 - b^2) = (√a^2 + √b^2)(√a^2 - √b^2)

(x^2 - (-81) = (x + √-81)(x - √-81)

we can remove the - from under the radical by multiplying it by i.

(x^2 - (-81) = (x + i√81)(x - i√81)

(x^2 - (-81) = (x + 9i)(x - 9i)

we can check our answer by using foil:

x^2 - 9ix + 9ix - 81i^2

x^2 - 81^2

i^2 = -1

x^2 + 81