Question

Use the Factor Theorem to find ALL zeros of f(x) = x^3 - x^2 - 11x + 15, given that 3 is a zero. Show all work and express zeros in exact form (no decimals).

Answer 1

Answer:

Step-by-step explanation:

by synthetic division

3) 1   -1   -11    15

|       3     6   -15   (add)

____________

   1     2    -5 |0

x²+2x-5=0

$x=\frac{-2 \pm\sqrt{2^{2} -4*1*-5} }{2*1} \\or~x=\frac{-2 \pm\sqrt{4+20} }{2} \\or~x=\frac{-2 \pm2\sqrt{6} }{2} \\or ~x=-1 \pm \sqrt{6}$