Solution:Given, -2 ≤ r ≤ -1, 4 ≤ q ≤ 5 and 6 ≤ p ≤ 8
Quantity I:
For minimum value p = 6, q = 4, and r = -2
[p(pq - r) + q(qr + p)]
= 6 × (6 × 4 - (-2)) + 4 × (4 × (-2) + 6)
= 6 × (24 + 2) + 4 × (-8 + 6)
= 156 + (-8) = 148
And for maximum value p = 8, q = 5, and r = -1
[p(pq - r) + q(qr + p)]
= 8 × (8 × 5 - (-1)) + 5 × (5 × (-1) + 8)
= 8 × (40 + 1) + 5 × (-5 + 8)
= 328 + 15 = 343
Thus, 148 ≤ Quantity I ≤ 343
Quantity II:
For minimum value p = 6, q = 4, and r = -2
[p² + pq - r² - rp]
= 36 + 24 - 4 + 12 = 68
And for maximum value p = 8, q = 5, and r = -1
[p² + pq - r² - rp]
= 64 + 40 - 1 + 8 = 111
Hence, 68 ≤ Quantity II ≤ 111
Therefore, Quantity I > Quantity II