1) 3x² + 6xy + 3y² = 3(x² + 2xy + y²) = 3(x + y)²

2) 3a² + 3b² - 6ab = 3(a² - 2ab + b²) = 3(a - b)²

3) 10m² + 20mn + 10n² = 10(m² + 10mn + n²) = 10(m + n)²

4) 7b² + 7 + 14b = 7(b² + 2b + 1) = 7(b + 1)²

5) 45p²q² - 30pq + 5 = 5(9p²q² - 6ab + 1) = 5(3pq - 1)²

6) 15x⁵y + 30x⁴y + 15x³y = 15x³y(x² + 2x + 1) = 15x³y(x + 1)²