a) (5x-2y)(x^2-xy+1). (x-1)(x+1)(x+2) c)1/2x^2 y^2(2x+y)(2x-y)

1 câu trả lời

\(\begin{array}{l} +)\;(5x - 2y)({x^2} - xy + 1)\\ = 5x.({x^2} - xy + 1) - 2y({x^2} - xy + 1)\\ = 5{x^3} - 5{x^2}y + 5x - 2{x^2}y + 2x{y^2} - 2\\ = 5{x^3} - 7{x^2}y + 5x + 2x{y^2} - 2\\ +)\;(x - 1)(x + 1)(x + 2)\\ = ({x^2} - 1)(x - 2)\\ = {x^2}(x - 2) - 1.(x - 2)\\ = {x^3} - 2{x^2} - x + 2 \end{array}\)