(a)Write down the binomial expansion of (1-y)^6 and simplify all the terms, (b) By putting y=x-x^2 in (a) deduce the expansion of (1-x x^2)^6 in ascending power of x as far as the term x^5 (c)By taking x=0.1 in (b) evaluate (0.91)^6 and correct to two decimal places