pre calculus
posted by Natasha on .
find the real zeros of f(x)=x^4+6x^311x^224x+28

try x=1
f(1) = 1+61124+28 = 0
so x1 is a factor
do synthetic division
(x^4+6x^311x^224x+28) = (x1)(x^3 + 7x  4  28)
x^3 + 7x^2  4x  28
= x^2(x+7)  4(x+7)
= (x+7)(x^  4)
so x^4+6x^311x^224x+28
= (x1)(x2)(x+2)(x+7)
x = 1, 2, 2, 7