Answer the questions that follow each situation. A mere yes or no will not merit any points. Cite the applicable provision in your explanation.

1. X entered into a contract with a corporation. In a suit against the corporation, its lawyer raises the defense that the contract was in violation of its by-laws. Is this defense tenable?
2. The authority given to the board of directors to amend its by-laws was revoked in a meeting of stockholders without previous notice that such matter could be acted upon in the meeting. Is the revocation valid?
3. A meeting of stockholders was improperly called and held. The business transacted at the meeting was questioned. What arguments can be raised to uphold its validity?
4. After the existence of a quorum has been determined in a meeting of stockholders, a number of them left the meeting, thereby leaving less than a quorum. Is the majority vote of those present sufficient to validly decide a matter properly presented?
5. X pledged his shares of stock to Y. as between them, who has the right to attend and vote at meetings of stockholders?