The graph of the equation 4x^2 - 12x + 4y^2 + 16y + 17 = -4x + 2y + 5 is a circle. Find the radius of the circle.
Simplify as
4x^2 - 8x + 4y^2 + 14y = -12 complete the sqiare on x, y
4(x^2 - 2x + 1) + 4(y^2 + [7/2] y + 49/ 16) = -12 + (4)(1) + 4 (49/16)
4 ( x-1)^2 + 4(y + 7/2)^2 = 17/4
The radius = sqrt (17) / 2