Question

HELP ME Using the following equation, complete the square and find the center and radius of the circle:
x2 + y2 + 4x − 6y − 12 = 0

You must show all work and calculations to receive credit.

Answer 1

Answer: $(-2,3)$, $r=5\ \text{units}$

Step-by-step explanation:

Given

the equation is $x^2+y^2+4x-6y-12=0$

completing the square

$\Rightarrow (x^2+2\times 2\times x+4-4)+(y^2-2\times3\times y+9-9)-12=0\\\Rightarrow (x^2+2\times 2\times x+4)+(y^2-2\times3\times y+9)-12-4-9=0\\\Rightarrow (x+2)^2+(y-3)^2=25\\\Rightarrow (x+2)^2+(y-3)^2=5^2\\\Rightarrow (x-(-2))^2+(y-3)^2=5^2$

Thus, the center of the circle is $(-2,3)$ and radius is $r=5\ \text{units}$