Question

Thực hiện phép tính: (5x+y)(x-2y)

Rút gọn: M=x(2-x)+2(x+1)(x-1)-(x-3)²

Answer 1

`(5x+y)(x-2y)=5x^2-10xy+xy-2y^2=5x^2-9xy-2y^2`

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`M=x(2-x)+2(x+1)(x-1)-(x-3)^2`

`M=2x-x^2+2x^2-2-x^2+6x-9`

`M=8x-11`