Let 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. What is the value of f(1)f(1)f(1)?
5
1
6
4