Problem 44331. Matrix Ax=B problem

Please improve the test suite. There are two glaring problems. First, there is only one test case—it is recommended that at least three be provided, though more are often necessary to prevent hard-coded workarounds. Second, do not provide the solution in the test case(s). For such a problem, the answer should be calculated beforehand and provided as a predefined number to hide the solution. Furthermore, candidate functions can be checked against the solution using an adequate error bound (perhaps within 1E-3) rather than isequal().