1. (3x + y)² 2. (x + y) ³ 3. (x - y) ³ 4. (3x + 2y) ²

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(3x + y)² = (3x)² + 2(3x)(y) + (y)²
= 9x² + 6 xy + y²

(x+y)³ = (x)³ + 3(x)²(y) + 3(x)(y)² + (y)³
= x³ + 3x²y + 3xy² + y³

(x -y)³ = (x)³ +3(x)²(-y)+ 3(x)(-y)² +(-y)³
= x³ - 3x²y + 3xy² - y³

(3x + 2y)² = (3x)² + 2(3x)(2y) + (2y)²
= 9x² + 12 xy + 4y²