What is the net effect of the under mentioned errors on the trial balance of a firm?

1. Total of sales was taken as P58,726 instead of P58,762.

2. A discount of P52 allowed to Mr. X was not posted in the discount account.

3. Sale of old furniture of P130 was credited to machinery account.

4. A credit sale for P250 to Mr. Y was posted twice in his account.