Question

simplify: (x+y)(2x+y)+(x+2y)(x-y)

Answer 1

x + y)(2x + y) + (x + 2y)(x - y)

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=> (2x² + xy + 2xy +y²) + (x² - xy + 2xy -2y²)

=> 2x² + x² + xy + 2xy - xy + 2xy + y² - 2y²

=>3x² + 4xy - y²