Proving Invalidity. Show That the Following Arguments Are Invalid

Q13: Symbolizing<br>-If something is heavy, then anyone who

Q14: Symbolizing<br>-Not all freshmen date every senior.

Q15: Prove valid<br>-<img src="https://d2lvgg3v3hfg70.cloudfront.net/TB100001/.jpg" alt="Prove valid - "

Q16: Prove valid<br>-<img src="https://d2lvgg3v3hfg70.cloudfront.net/TB100001/.jpg" alt="Prove valid - "

Q17: Symbolizing<br>-If anything is heavy, then there is

Q19: Symbolizing<br>-No freshmen date any seniors.

Q20: Translations. <br>Letting Hxy = "x is heavier

Q21: Translations. <br>Letting Hxy = "x is heavier

Q22: Theorems of logic. <br>Prove that the following

Q23: Symbolizing<br>-Some freshmen date no seniors.