private String formatMonome(int exponent, int coeficient) {
        if (coeficient == 0) {
            return "";
        }
        if (exponent == 0) {
            if (exponent == this.getMaximumExponent())
                 return "" + coeficient;
            else return (coeficient > 0) ? "+" + coeficient : coeficient + "";
        }

        String exponentString = (exponent == 1) ? "" : exponent + "";
        String coeficientString;
        if (coeficient == 1) {
            coeficientString = "+";
        } else if (coeficient == -1) {
            coeficientString = "-";
        } else {
            coeficientString = (coeficient > 0) ? "+" + coeficient : coeficient + "";
        }

        return coeficientString + "x" + exponentString;
    }