Clustering using R

Hi. I wish to use the elbow and silhouette method and plot the graph for the following data but keep getting an error. Please tell me how i can correct the codes.

Point 1: (7,3)

Point 2: (4,5)

Point 3: (2,4)

Point 4: (0,1)

Point 5: (9,7)

Point 6: (6,8)

Here are my codes:

X <- matrix(c(7,3,4,5,2,4,0,1,9,7,6,8),nrow=6,byrow= TRUE)

res.k <- kmeans( X, centers= X[c(5,6),], algorithm = "Lloyd")

library(factoextra)

library(NbClust)

library(cluster)

fviz_nbclust(X, kmeans, method= "wss")

fviz_nbclust(X, kmeans, method= "silhouette")

fviz_cluster(res.k, X, ellipse.type= "norm")

The last three codes here give an error, please correct them. Thanks

The points are given. Need to find the optimal amount of clusters using R. So use the elbow and silhouette method on R