I did (p + q)^2 = p^2 + 2pq + q^2 g ≥ 4pq
so p^2 -2qr + q^2 ≥ 0 which is true since it's equal to (p-q)^2 and any number squared is ≥ 0.
Since (p - q)^2 + 4pq = (p + q)^2 and (p - q)^2 ≥ 0
(p + q)^2 ≥ 4pq so
p + q ≥ sqrt (4 pq)
The solution bank added the line p and q are both positive
so p > 0 and q > 0
Therefore, p + q > 0
Why is this necessary? Doesn't the line "...(p-q)^2 and any number squared is ≥ 0 " eliminate the need for it, since it shows that 4qr is the value that (p +q)^2 is equal or greater than?