Question

Find the center of the circle whose equation is 3x² + 3y² = 75.

(-3, -3)
(0, 0)
(3, 3)

Answer 1

A nice general equation of a circle is (x-h)^2 + (y-k)^2 = r^2, where (h,k) is the centre of the circle and r = the radius of the circle.
If we divide both sides of the equation by 3, we would have the equation in the above form, and be able to work out both the radius and the centre of the circle.

Answer 2

So, what do we get if we divide both sides by 3?

Answer 3

If i remember right you complete the square.