Question

упростите выражение (y-9)(3y-1)-(2y+1)(5y-7)

Answer 1

 (y-9)(3y-1)-(2y+1)(5y-7)=3y²-y-27y+9-10y²+14y-5y+7=-7y²-19y+16

Answer 2

$(y-9)(3y-1)-(2y+1)(5y-7)= \\=3y^2-y-27y+9-(10y^2-14y+5y-7)= \\=3y^2-28y+9-10y^2+9y+7=-7y^2-19y+16$