@Override
	public String toString() {
		if (isVertical) {
			return "[x=" + value + "]";
		} else if (isHorizontal) {
			return "[y=" + value + "]";
		} else {
			String b = String.format("%+f", this.b);
			return "[y=" + this.k + "*x" + b + "]";
		}
	}