-2.5=P+7.1
We want to isolate P.
Hence, we must move 7.1 to the left hand side, this can be given by
![-2.5-7.1=P](https://img.qammunity.org/2023/formulas/mathematics/college/opvfvll82v6vnodir4no1mnoupcab8675j.png)
that is, since 7.1 is adding to P on the right hand side, when you move it to the left hand side
7.1 must substract -2.5.
Finally, since
![-2.5-7.1=-9.6](https://img.qammunity.org/2023/formulas/mathematics/college/6me6ih3lypd48pltx5uu20rit5w39aukav.png)
we have that
![P=-9.6](https://img.qammunity.org/2023/formulas/mathematics/college/g54q6jb2cg7e6qsnpy1sklsjdyjqgiki0d.png)