Write the complex number # (2x+i)^3# in standard form?
1 Answer
Dec 31, 2015
Explanation:
#(a+b)^3 = a^3+3a^2b+3ab^2+b^3#
So:
#(2x+i)^3#
#= (2x)^3+3(2x)^2(i)+3(2x)(i)^2+(i)^3#
#=8x^3+12x^2 i - 6x -i#
#=(8x^3-6x) + (12x^2-1)i#
