Evaluate m2(n-1) given m=2 and n=2/3. Calculate the area of the outer material of a pipe with inner diameter 7 cm and outer diameter 14 cm, using pi = 3.14.

Given $m = 2$ and $n = \frac{2}{3}$.
The expression is $m^2(n-1)$.

The value of $m^2(n-1)$ is $\boxed{-\frac{4}{3}}$.

b) (i)

Inner diameter = $7 \text{ cm}$, so inner radius $r_1 = \frac{7}{2} \text{ cm} = 3.5 \text{ cm}$.
Outer diameter (total diameter including insulation) = $14 \text{ cm}$, so outer radius $r_2 = \frac{14}{2} \text{ cm} = 7 \text{ cm}$.

This is the area of the larger circle minus the area of the smaller circle.
The formula for the area of a circle is $A = \pi r^2$.
Area of outer material $= \pi r_2^2 - \pi r_1^2 = \pi (r_2^2 - r_1^2)$.

The total area occupied by the outer material is $\boxed{115.495 \text{ cm}^2}$.

b) (ii)

Area of outer material $= 115.495 \text{ cm}^2$.

Cost per cm$^2$ = GHe 2.00.

The total cost to install the outer material is $\boxed{\text{GHe } 230.99}$.