20/11/14 00:20:47.79 Ju5i+5P/.net
A = (2, 0), B = (1, √3), C = (-1, √3), D = (-2, 0), E = (-1, -√3), F = (1, -√3)
AC+2DE-2FA = C-A+2(E-D)-2(A-F) = C-A+2E-2D-2A+2F = -3A+C-2D+2E+2F
= -3(2, 0)+(-1, √3)-2(-2, 0)+2(-1, -√3)+2(1, -√3)
= (-6, 0)+(-1, √3)+(4, 0)+(-2, -2√3)+(2, -2√3) = (-3, -3√3)