а) (2x - y)(x + y) = 2x^2 + 2xy - yx - y^2 = 2x^2 + xy - y^2
б) (a + b)(2a + 3b) = 2a^2 + 3ab + 2ab + 3b^2 = 2a^2 + 5ab + 3b^2
в) (3c + a)(2c - a) = 6c^2 - 3ac + 2ac - a^2 = 6c^2 - a^2
г) (6z - y)(2z - y) = 12z^2 - 6zy - 2yz + y^2 = 12z^2 - 8zy + y^2
а) (2x - y)(x + y) = 2x^2 + 2xy - yx - y^2 = 2x^2 + xy - y^2
б) (a + b)(2a + 3b) = 2a^2 + 3ab + 2ab + 3b^2 = 2a^2 + 5ab + 3b^2
в) (3c + a)(2c - a) = 6c^2 - 3ac + 2ac - a^2 = 6c^2 - a^2
г) (6z - y)(2z - y) = 12z^2 - 6zy - 2yz + y^2 = 12z^2 - 8zy + y^2