If f(x)=3x4−4x3−12x2+5f(x) = 3x^4 - 4x^3 - 12x^2 + 5f(x)=3x4−4x3−12x2+5, find the x-coordinate of the local minimum.
−1,2-1, 2−1,2
000
222
−1-1−1