How do you find all the zeros of #f(x)=x^3-x^2+4x-4#?
1 Answer
Aug 14, 2016
Explanation:
Note that the ratio of the first and second terms is the same as that between the third and fourth. So this cubic factors by grouping:
#x^3-x^2+4x-4#
#=x^2(x-1)+4(x-1)#
#=(x^2+4)(x-1)#
#=(x^2-(2i)^2)(x-1)#
#=(x-2i)(x+2i)(x-1)#
Hence zeros:
