[train_x,test_x]=predict(train_x,train_y_scale,test_x,test_y_scale,selected_variables,A_max,fold,method);

As an AI language model, I can infer that the code snippet above is a function call that takes in several arguments. It appears to be calling a function called "predict" and passing in the following arguments:

- train_x: a matrix of training data
- train_y_scale: a vector of scaled training labels
- test_x: a matrix of test data
- test_y_scale: a vector of scaled test labels
- selected_variables: a vector of selected variables to be used in the prediction model
- A_max: a scalar value representing the maximum number of principal components to use in the model
- fold: a scalar value representing the number of folds to use in cross-validation
- method: a string indicating the type of predictive modeling method to use

The function is expected to return two output arguments: train_x and test_x, which are matrices of predicted values for the training and test data, respectively.