Linear combination using classical linear discriminate

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I have two bivariate variables with means and variances differ by group (diseased, non-diseased). No dependent variable (binary variables). I would like to make a linear combination using classical linear discriminate.
X1D ….N(0.5, 2), X2D ….N(0.5, 2)
X1N ….N(0, 1), X2N ….N(0, 1)

Where D stands for diseased and N is non-diseased.
Any helps PLZ
Thanks..