Question

Using the given zero, find all other zeros of f(x). -2i is a zero of f(x) = x^4 - 45x^2 - 196

Answer 1

Hello,

$\begin{array}{c|c|c|c|c|c|c|}&x^4&x^3&x^2&x&1\\ &1&0&-15&0&-196\\x=2i&&2i&-4&-96i&196\\x=-2i&&-2i&0&98i&\\ &1&0&-49&0&\\x=7&&7&49&&\\&1&7&0&&\\x=-7&&-7&0&&\\&1&0&&&\\ \end{array}\right]$

zeroes are 2i,-2i,7,-7