Consider the function f(x)=x2−4x+4+x2+6x+9f(x) = \sqrt{x^2 - 4x + 4} + \sqrt{x^2 + 6x + 9}f(x)=x2−4x+4+x2+6x+9. Find the interval where f(x)f(x)f(x) is constant.
[−3,2][-3, 2][−3,2]
(−∞,−3](-\infty, -3](−∞,−3]
[2,∞)[2, \infty)[2,∞)
The function is not constant on any interval.