i. Number of coefficients = 5
∴ Degree = 5 – 1 = 4
∴ Index form = 3x4 – 2x3 + 0x2 + 7x + 18
ii. Number of coefficients = 4
∴ Degree = 4 – 1 = 3
∴ Index form = 6x3 + x2 + 0x + 7
iii. Number of coefficients = 4
∴ Degree = 4 – 1 = 3
∴ Index form = 4x3 + 5x3 – 3x + 0