Find the value of xxx for which f(x)=x2−4x+7f(x) = x^2 - 4x + 7f(x)=x2−4x+7 has a derivative of 000 (i.e., local extremum).
x=1x = 1x=1
x=2x = 2x=2
x=3x = 3x=3
x=4x = 4x=4