Question

Find all of the real and imaginary zeros for the polynomial function. f(x)=X^3-4x^2-36x+144

Answer 1

I know one of the zeros is positive 4. The other one I had down was plus or minus 6i (This was circled and I was given half credit). What's wrong with this?

Answer 2

@campbell_st

Answer 3

\[x^3-4 x^2-36x+144=(x-6) (x-4) (x+6) \]

Answer 4

Ok... so if 4 is a zero then (x - 4) is a factor so a little division again



so the factors are

\[(x-4)(x^2 - 36)\]

factor the quadratic, which is the difference of 2 squares...

for the 3 linear factors