1) p² - 2pq + q² = (p - q)²
2) u² + 2uv + v² = (u + v)²
3) z² - 20z + 100 = (z - 10)²
4) 64 + 16y + y² = (8 + y)²
5) 9a² + 6at + t² = (3a + t)²
6) m² + 121v² - 22mv = m² - 2 * m * 11v + (11v)² = (m - 11v)²
7) 56bc + 16b² + 49c² = (4b)² + 2 * 4b * 7c + (7c)² = (4b + 7c)²
8) -20dx + 4d² + 25x² = (2d)² - 2 * 2d * 5x + (5x)² = (2d - 5x)²
9) 144a² + 81b² + 216ab = (12a)² + 2 * 12a * 9b + (9b)² = (12a + 9b)²
10) 25x² - 110cx + 121c² = (5x)² - 2 * 5x * 11c + (11c)² = (5x - 11c)²
11) 400t² + 120bt + 9b² = (20t)² + 2 * 20t * 3b + (3b)² = (20t + 3b)²
12) 256u² - 416au + 169a² = (16u)² - 2 * 16u * 13a + (13a)² = (16u - 13a)²
13) 4a⁴ + 20a²b² + 25b⁴ = (2a²)² + 2 * 2a² * 5b² + (5b²)² = (2a² + 5b²)²
14) 16x⁴ - 72x²y³ + 81y⁶ = (4x²)² - 2 * 4x² * 9y³ + (9y³)² = (4x² - 9y³)²
15) 100c⁶ + 64d⁸ + 160c³d⁴ = (10c³)² + 2 * 10c³ * 8d⁴ + (8d⁴)² = (10c³ + 8d⁴)²