public static String assertRationalMatrices(double[][] first,
			double[][] second) {

		String rational = assertRationalMatrix(first);

		if (rational != null) {

			return rational;

		}

		rational = assertRationalMatrix(second);

		if (rational != null) {

			return rational;

		}

		if (first.length != second.length) {

			return "The matrices do not have the same number of rows:"
					+ NEWLINE + NEWLINE + representMatrix(first, 3) + NEWLINE
					+ NEWLINE + representMatrix(second, 3);

		}

		if (first[0].length != second[0].length) {

			return "The matrices do not have the same number of columns:"
					+ NEWLINE + NEWLINE + representMatrix(first, 3) + NEWLINE
					+ NEWLINE + representMatrix(second, 3);

		}

		return null;

	}