Parabol \(\displaystyle y = 3x^2– 2x+1\) có đỉnh là:
(A) \(\displaystyle I( - {1 \over 3}; \, {2 \over 3})\)
(B) \(\displaystyle I( - {1 \over 3}; \, - {2 \over 3})\)
(C) \(\displaystyle I({1 \over 3}; \, - {2 \over 3})\)
(D) \(\displaystyle I({1 \over 3}; \, {2 \over 3})\)