How do you simplify #5(x - 4)(x + 1 + i)(x - 1 - i)#?
1 Answer
May 22, 2018
Explanation:
#"expand the factors in pairs and multiply the expansions"#
#rArr5(x-4)=5x-20#
#((x+1)+i)((x-1)-i)larrcolor(blue)"expand using FOIL"#
#=(x+1)(x-1)-i(x+1)+i(x-1)-i^2#
#=x^2-1-x i-i+x i-i+1toi^2=-1#
#=x^2-2i#
#rArr(5x-20)(x^2-2i)#
#=5x^3-10x i-20x^2+40i#
