7p+12=15-7p

$${\mathtt{7}}{\mathtt{\,\times\,}}{\mathtt{p}}{\mathtt{\,\small\textbf+\,}}{\mathtt{12}} = {\mathtt{15}}{\mathtt{\,-\,}}{\mathtt{7}}{\mathtt{\,\times\,}}{\mathtt{p}}$$

$${\mathtt{14}}{\mathtt{\,\times\,}}{\mathtt{p}}{\mathtt{\,\small\textbf+\,}}{\mathtt{12}} = {\mathtt{15}}$$

$${\mathtt{14}}{\mathtt{\,\times\,}}{\mathtt{p}} = {\mathtt{3}}$$

$${\mathtt{p}} = {\frac{{\mathtt{3}}}{{\mathtt{14}}}}$$  or 0.2142857142857143...

What do you want me to do with it?

7p+12=15-7p

14p=3

p= $${\frac{{\mathtt{3}}}{{\mathtt{14}}}} = {\mathtt{0.214\: \!285\: \!714\: \!285\: \!714\: \!3}}$$