17. Expand and simplify. Use the binomial theorem. a) a b + 2) 3 b) a - a )* C) 1 - X16 d ) (2 x2 - 1) 18. a) Determine the middle term in the expansion of (a - 363) 8. b) Determine the term containing x1 in the expansion of (x2 _ 1)1 (19./a) Determine the constant term in the expansion (x2 _ 2 12 b) What is the constant term in the expansion of (y - 1 y z ? 20. One term in the expansion of (2x - m) is -15 120xty3. Determine m