Step-by-step explanation:
[tex]2p + q = 3 \\ p - 5q = 7 \\ \\ multiply \: the \: second \: equation \: by \: 2 \\ 2p - 10q = 14 \\ 2p - 10q - (2p + q) = 14 - 3 \\ 2p - 10q - 2p - q = 11 \\ - 11q = 11 \\ q = - 1 \\ \\ 2p + q = 3 \\ 2p - 1 = 3 \\ 2p = 4 \\ p = 2[/tex]