[latex]a)(x+3y)(2x+y)-6xy-2x^2 = \2x^2+xy+6xy+3y^2-6xy-2x^2 =\xy+3y^2\\b)3(2x^2y-3xy^2)-3x(x+y^2) = \6x^2y-9xy^2-3x^2-3xy^2=\6x^2y-12xy^2-3x^2\\c)(2ab^2-a^2b^2+a^3)*2a^2b = \4a^3b^3-2a^4b^3+2a^5b\\d)(6a^2b-8ab^2):(2ab) = \\frac{6a^2b}{2ab} - frac{8ab^2}{2ab} = \\3a -4b[/latex]
[latex]a)\(x+3y)(2x+y) -6xy-2x^{2}=\\=2x^{2}+xy+6xy+3y^{2}-6xy-2x^{2}=xy+3y^{2}\\b)\3(2x^{2}y-3xy^{2}) - 3x(x+y^{2}) =\\= 6x^{2}y - 9xy^{2} - 3x^{2}-3xy^{2} = 6x^{2}y -12xy^{2}-3x^{2}\\c)\(2ab^{2}-a^{2}b^{2}+a^{3})*2a^{2}b = \\= 4a^{3}b^{3}-2a^{4}b^{3}+2a^{5}b\\d)\(6a^{2}b-8ab^{2}):(2ab) = 2ab(3a-4b):(2ab) = 3a-4b[/latex]
