Odpowiedź:
[tex]a)\ \ (-3c+2d)(2c-6)=-6c^2+18c+4cd-12d\\\\b)\ \ (-10m+3n)(5n-4)=-50mn+40m+15n^2-12n\\\\c)\ \ (9s-2t)(7t-s)=63st-9s^2-14t^2+2st=65st-9s^2-14t^2\\\\d)\ \ (3a+5b)(2a+7b)=6a^2+21ab+10ab+35b^2=6a^2+31ab+35b^2\\\\e)\ \ (4m-3n)(5m-n)=20m^2-4mn-15mn+3n^2=20m^2-19mn+3n^2\\\\f)\ \ (-3x-5y)(2x+4y)=-6x^2-12xy-10xy-20y^2=-6x^2-22xy-20y^2[/tex]