Let (x,y) be an ordered pair of real numbers that satisfies the equation x^2 + y^2 = 14x + 40y. What is the minimum value of x?
Re-arrange this circle equation to standard form to find the center and the radius
x^2 -14x + y^2 -40y = 0
(x-7)^2 + (y-20)^2 = 49 + 400
center is 7,20 radius is sqrt 449
minumum x would be 7 - sqrt 449