F (x) = x3 + 4x2 + x - 6 real zeros

Hello,

f (x) = x^3+4x²+x-6

=x^3-x²+5x²-5+x-1

=x² (x-1) + 5 (x-1) (x+1) + x-1

= (x-1) (x²+5x+5+1)

= (x-1) (x²+2x+3x+6)

= (x-1) (x (x+2) + 3 (x+2))

= (x-1) (x+2) (x+3)

Zeros are 1,-2,-3.