Question

Which are real zeroes of this function?
x3 + 2x2 – 9x – 18

Answer 1

\[x^3 + 2x^2 – 9x – 18=(x^3 + 2x^2 ) -(9x+18 ) = \]
\[(x^3 + 2x^2 ) -(9x+18 ) = x^2(x+2) -9(x+2)\]
\[x^2(x+2) -9(x+2) = (x+2)(x^2-9)\]

can you go on ?