For this case we have the following equation:
[tex]p + 2p + 3p = 12[/tex]
To solve we follow the steps below:
We add similar terms from the left side of the equation:
[tex]6p = 12[/tex]
We divide between 6 on both sides of the equation:
[tex]p = \frac {12} {6}\\p = 2[/tex]
Finally, we have to:
[tex]5p-1 = 5 (2) -1 = 10-1 = 9[/tex]
Answer:
[tex]p = 2\\5p-1 = 9[/tex]