Question

Add:
(2p- q + 2pq) + (2q-r + 2qr) + (2r-p+2pr)​

Answer 1

$(2p - q + 2pq) + (2q - r + 2qr) \\ + (2r - p + 2pr) \\ \\ = 2p - q + 2pq + 2q - r + 2qr + \\ 2r - p + 2pr \\ \\ = 2p - p - q + 2q - r + 2r + 2pq \\ + 2qr + 2pr \\ \\ = p + q + r + 2(pq + qr \: + pr)$