underdetermined

In mathematics, a system of linear equations (or linear system) is a collection of linear equations involving the same set of variables. For example, is a system of three equations in the three variables . A solution to a linear system is an assignment of numbers to the variables such that all the equations are simultaneously satisfied. A solution to the system above is given by since it makes all three equations valid.
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rival hypotheses to explain the facts are "underdetermined" when they are equally consistent with the available evidence.  There is a question if every scientific theory must always remain underdetermined.