1) 2x(x3-5x2+2) =
2) (a+5)*(2a-7) =
3) (9x-y)(4x-3y) =
4) 9m2-12mm
5) 15x6-5x4 =

1)2х(х^3-5х^2+2)=2х^4-10х^3+4х2)(а+5)(2а-7)=2а^2-7а+10а-35=2а+3а-353)(9х-у)(4х-3у)=36х^2-27ху-4ху+3у^2=36х^2-31ху+3у^24)9м^2-12мм=9м^2-12м^2=-3м^25)15х^6-5х^4=15х^4*х^2-5х^4=5х^4(3х^2-1)