Correct Answer: 10a ² – 14ab

Solution : Given: (a – 2b)(b – 3a) + (a + b)(a – 3b) – (b – 3a)(4a – 5b)
= (a – 2b)(–3a + b) + (a + b)(a – 3b) – (b – 3a)(4a – 5b)
= –3a ² + 6ab + ab – 2b ² + a ² + ab – 3ab – 3b ² – (4ab –12a ² – 5b ² + 15ab)
= –2a ² + 5ab – 5b ² – 19ab + 12a ² + 5b ²
= 10a ² – 14ab
Hence, the correct answer is 10a ² – 14ab.