5x(x-y)-(x+y)(5x-y) пж помогиье срочно

5x(x-y)-(x+y)(5x-y)5x^2-5xy-(5x^2-xy+5xy-y^2)5x^2-5xy-(5x^2+4xy-y^2)5x^2-5xy-5x^2-4xy+y^2-9xy+y^2