How do you find the term containing #x^3# in the expansion of #(2-3x)^8#?
1 Answer
Jul 23, 2017
Explanation:
#"using the "color(blue)"binomial theorem"#
#(a+b)^n=sum_(r=0)^n((n),(r))a^((n-r))b^r#
#"where "((n),(r))a^((n-r))b^r" is the general term"#
#"and "T_(r+1)=((n),(r))a^((n-r))b^r#
#"using r = 3-that is the fourth term"#
#"here " a=2" and "b=-3x#
#rArr((8),(3))2^5.(-3x)^3#
#=56xx32xx-27x^3#
#=48384x^3#
