(1) ?
(2) (5-3√3, 3+6√3)
(3.1) (11, -2, 7)
(3.2) m=6, n=-4
(4.1) 0.818
(4.2) 213
(5) π-2
(6) -(a-b)(b-c)(c-a)
(7) sinx/x