Use the binomial theorem to expand [2-1/4 x]^5

Answer 1

You should know that the row from Pascal's triangle needed here are
1 5 1010 5
Then (2 - x/4)^5
= 1(2)^5 - 5(2^4)(x/4) + 10(2^3)(x/4)^2 - 10(2^2)(x/4)^3 + 5(2)(x/4)^4 - (x/4)^5
= 32 - 20x + 5x^2 - (5/8)x^3 + (5/128)x^4 - (1/1024)x^5