The equation of a circle is x2+y2+8x−14y+56=0 . what is the radius of the circle?

Step-by-step explanation:

The equation of the circle in center-radius form is:

Where the point is the center of the circle and "r" is the radius.

Subtract 56 from both sides of the equation:

Make two groups for variable "x" and variable "y":

Complete the square:

Add inside the parentheses of "x".

Add   inside the parentheses of "y".

Add and to the right side of the equation.

Then:

Rewriting, you get that the equation of the circle in center-radius form is:

You can observe that the radius of the circle is:

answer: c

(2, -4)

goes 7 to the

(9, 4)

easy