白鹅潭是珠江广州河道的交汇处，是西航道、前航道、后航道的起始点。
路点“沙面”位于白鹅潭北岸，这里有一块铭牌写着“前左 0+000”，表示此处是前航道左岸的0公里起始点。
路点“洲头咀”位于白鹅潭的东南岸，这里的铭牌写着“后左 0+000”，表示此处是后航道左岸的0公里起始点。
从白鹅潭到白蚬壳码头的航程是2X00米，所以位于路点“白蚬壳码头”的铭牌写着“后左 2+X00”。
请您求得X的值，然后去找“前左 2+X00”铭牌，宝藏位于其附近十米范围内。
Baietan, which literally means "White Swan Pond", marks the junction of three reaches of the Pearl River: the West Reach, the Front Reach, and the Back Reach.
The waypoint "Shamian" is located on the northern bank of Baietan, where a plaque labelled "Front Left 0+000," denotes the starting point of the left bank of the Front Reach.
Located on the southeastern bank of Baietan, the waypoint "Zhoutouzui" hosts a plaque inscribed with "Back Left 0+000," designating the starting point of the left bank of the Back Reach.
The distance between Baietan and Baixianke Wharf spans 2X00 meters. Thus, the plaque at the "Baixianke Wharf" waypoint reads "Back Left 2+X00."
Please determine the value of X, then locate the plaque labelled "Front Left 2+X00." The cache lies within 10 meters of this marker.