The diagram shows the net of an open box of height 3 cm. The area of the base of the box is 15 cm². The length of the rectangular base is x cm. The total area of the net is A cm².

1. (a)Show that A = 15 + 6x + 90/x.[2]
2. (b)Graham has one of these open boxes. The total area of the net of his box is 65 cm². Write down an equation in x and solve it to find the length of the base of Graham's box. Give your answer correct to 2 decimal places.[4]
3. (c)(i)Complete the table below for A = 15 + 6x + 90/x. x 2 3 4 5 6 7 8 A 72 63 61.5 63 66 69.9[1]
4. (c)(ii)Draw the graph of A = 15 + 6x + 90/x for 2 ≤ x ≤ 8.[2]
5. (c)(iii)Delilah has one of these open boxes. The area of the net of her box is 68 cm². Use your graph to find the length and width of Delilah's box.[2]

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