Question

how to get the roots of u^3-3u^2-4

Answer 1

to get the possible zeroes:

a = get +&- factors of -4:
\[\pm1,\pm2,\pm4\]
b = then get the +&- factors of coefficient of the highest degree, which is u^3, with coefficient of 1:
\[\pm1\]
then get all possible quotients of a/b:
\[\pm1,\pm2,\pm4\]
then use trial and error synthetic division to get at least one factor. let's use x+1:
1 -3 0 -4 ||-1
-1 -4 4
1 -4 -4 0<----- you got a zero, meaning x+1 is a root!
to get the other root:
1x^2-4x-4=0 (from the 1 -4 -4 0 that we got)
(x-2^2)=0

roots:(x+1), (x+2) of multiplicity 2

Answer 2

nice one, bro :))

Answer 3

(x-2)^2=0, i mean, not (x-2^2)=0

Answer 4

don't understand... did you do guess work to see who the equation equals to zero?