Question

What is the center and radius of the circle with equation (x + 6)2 + (y − 4)2 = 36?

Answer 1

Centre = (-6, 4), radius = 6

Explanation:

To find the coordinates of the centre we make each bracket equal to zero.

This gives us x = -6 and y = 4, so the coordinates are (-6, 4).
As for the radius, when the equation is in this form, the constant is equal to the radius², so the radius will be √36 = 6.