(a)(i) \(\boxed{\text{Rotation }90^\circ\text{ anticlockwise about }(0,0)}\). The rule \((x,y)\mapsto(-y,x)\) maps the three vertices onto B.

(a)(ii) \(\boxed{\text{Enlargement with scale factor }-2\text{ and centre }(0,-2)}\). For example, \((2,-4)\) has displacement \((2,-2)\) from the centre; multiplying by −2 gives \((-4,4)\), producing image \((-4,2)\).

(b)(i) Negate each x-coordinate. The reflected vertices are \(\boxed{(-1,-4),(-2,-4),(-2,-2)}\).

(b)(ii) Subtract 1 from x and add 3 to y. The translated vertices are \(\boxed{(0,-1),(1,-1),(1,1)}\).