### Question:
LinearAlgebraUtils { public static double[] solve33(double[][] A, double[] rhs) throws IllegalArgumentException { double[] result = new double[3]; if (A[0].length != 3 || A.length != 3) { throw new IllegalArgumentException("solve33: input: size of A not 33."); } if (rhs.length != 3) { throw new IllegalArgumentException("solve33: input: size rhs not 3x1."); } final double L10 = A[1][0] / A[0][0]; final double L20 = A[2][0] / A[0][0]; final double U11 = A[1][1] - L10 * A[0][1]; final double L21 = (A[2][1] - (A[0][1] * L20)) / U11; final double U12 = A[1][2] - L10 * A[0][2]; final double U22 = A[2][2] - L20 * A[0][2] - L21 * U12; final double b0 = rhs[0]; final double b1 = rhs[1] - b0 * L10; final double b2 = rhs[2] - b0 * L20 - b1 * L21; result[2] = b2 / U22; result[1] = (b1 - U12 * result[2]) / U11; result[0] = (b0 - A[0][1] * result[1] - A[0][2] * result[2]) / A[0][0]; return result; }  static double[] solve22(double[][] A, double[] y); static double[] solve33(double[][] A, double[] rhs); static DoubleMatrix absMatrix(DoubleMatrix inMatrix); static double[][] absMatrix(double[][] inMatrix); static DoubleMatrix matrixPower(DoubleMatrix data, double scalar); static double[][] matrixPower(double[][] inMatrix, double scalar); static void invertChol_inplace(double[][] inMatrix); static double[][] invertChol(double[][] inMatrix); static void invertChol_inplace(DoubleMatrix inMatrix); static DoubleMatrix invertChol(DoubleMatrix inMatrix); static ComplexDoubleMatrix dotmult(ComplexDoubleMatrix A, ComplexDoubleMatrix B); static void dotmult_inplace(ComplexDoubleMatrix A, ComplexDoubleMatrix B); static void fliplr_inplace(DoubleMatrix A); static DoubleMatrix matTxmat(DoubleMatrix matrix1, DoubleMatrix matrix2); static ComplexDoubleMatrix matTxmat(ComplexDoubleMatrix matrix1, ComplexDoubleMatrix matrix2); static void wshift_inplace(DoubleMatrix inVector, int n); static DoubleMatrix wshift(DoubleMatrix inMatrix, int n); static void setdata(DoubleMatrix outMatrix, Window outWin, DoubleMatrix inMatrix, Window inWin); static void setdata(ComplexDoubleMatrix outMatrix, Window outWin, ComplexDoubleMatrix inMatrix, Window inWin); static void setdata(ComplexDoubleMatrix outMatrix, ComplexDoubleMatrix inMatrix, Window inWin); static void setdata(DoubleMatrix outMatrix, DoubleMatrix inMatrix, Window inWin); static void chol_inplace(double[][] inMatrix); static void chol_inplace(DoubleMatrix inMatrix); static void invert_inplace(double[][] inMatrix); static double[][] invert(double[][] inMatrix); static void invert_inplace(DoubleMatrix inMatrix); static DoubleMatrix invert(DoubleMatrix inMatrix); static void arrangeCholesky_inplace(DoubleMatrix inMatrix); static void arrangeCholesky_inplace(double[][] inArray);  }### Answer:
@Test public void testSolve33() throws Exception { double[] SOL_33_ACTUAL = LinearAlgebraUtils.solve33(A_PASCAL_33.toArray2(), X_33); Assert.assertArrayEquals(SOL_33_EXPECTED, SOL_33_ACTUAL, DELTA); }