private static StringBuilder buildCoefficient(final int n, final boolean absolute) {
        final StringBuilder sb = new StringBuilder();
        if (n == 0) 
            return sb;
        
        sb.append(n > 0 ? " + " : " - ");
        if ((absolute) || (Math.abs(n) != 1))
            sb.append((n > 0) ? n : -n);
        return sb;
    }