How to excel with the following computing?

Excel in how to carry out the calculation formula:Z = X (1-Y) / 0.86
of which have X and Y data, and Z

A1 = X, B1 = Y (data entry into the cell)
in the C1 fill = A1 * (1-B1) / 0.86 would be defined as any out X; out any further definition Cheng Y;
and then out any input = X * (1-Y) / 0.86
down to copy.
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