1.(xy+x²y²)(x²y+xy²) 2.(2a²-5b²)(3a²+4b²) 3.(5x²-6y²)(6x²-5y²) 4.(x²+2x+1)(x+3)

1. (xy + x²y²)(x²y + xy²) = x³y² + x²y³ + x⁴y³ + x³y⁴ 2. (2a² - 5b²)(3a² + 4b²) = 6a⁴ + 8a²b² - 15a²b² - 20b⁴ = 6a⁴ - 7a²b² - 20b⁴ 3. (5x² - 6y²)(6x² - 5y²) = 30x⁴ - 25x²y² - 36y⁴ + 30x²y² = 30x⁴ + 5x²y² - 36y⁴ 4. (x² + 2x + 1)(x + 3) = x³ + 2x² + x + 3x² + 6x + 3 = x³ + 5x² + 7x + 3