If - 1 is a zero then
[tex](x + 1)[/tex]
is a factor.
Dividing with this factor using the long division approach, we get the quadratic factor to be,
[tex]4 {x}^{2} + 3x - 10[/tex]
(see attachment).
We can rewrite the polynomial as
[tex]f(x) = (x + 1)(4 {x}^{2} + 3x - 10)[/tex]
We can further factor as
[tex]f(x) = (x + 1)(4 {x}^{2} - 5x + 8x - 10)[/tex]
That is
[tex]f(x) = (x + 1)(x + 2)(4x - 5)[/tex]
