Answer:
The 20th term in the expansion of (a + b)^22 can be found using the binomial theorem. The general term in the expansion of (a + b)^n is given by:
T_r = (n choose r) a^(n-r) b^r
where (n choose r) is the binomial coefficient, which is equal to n! / (r! (n-r)!).
Therefore, the 20th term in the expansion of (a + b)^22 is:
T_20 = (22 choose 20) a^(22-20) b^20
= (22 choose 20) a^2 b^20
Using the formula for the binomial coefficient, we have:
(22 choose 20) = 22! / (20! 2!) = (22*21) / 2 = 231
Substituting this value into the expression for T_20, we get:
T_20 = 231 a^2 b^20
Therefore, the 20th term in the expansion of (a + b)^22 is 231 a^2 b^20.