Question

Find all the zeros of the polynomial function f(x) = x + 2x² - 9x - 18 a) (-3) b) (-3. -2,3) c) (-2) d) (-3.2.3) e) none

Answer 1

Answer:x=-3,-2,3

Step-by-step explanation:

Given equation of polynomial is

$x^{3}+2x^2-9x-18=0$

taking $x^3$ and -9x together and remaining together we get

$x^3-9x+2x^2-18=0$

$x\left ( x^2-9\right )+2\left ( x^2-9\right )$

$x\left ( \left ( x+3\right )\left ( x-3\right )\right )+2\left ( \left ( x+3\right )\left ( x-3\right )\right )$

$taking \left ( x+3\right )\left ( x-3\right ) as common$

$\left ( x+2\right )\left ( x+3\right )\left ( x-3\right )=0$

therefore

x=-3,-2,3