`f (x) = 2x^4 - 4x^3 - 7x - 14`
`= 2x^3(x - 2) - 7x - 14`
`= 2x^{2}.x.(x - 2) - 7x - 14`
`-> f (1 + sqrt{3})`
`= 2.(1 + sqrt{3})^{2}.(1 + sqrt{3}).(sqrt{3} - 1) - 7(1 + sqrt{3}) - 14`
`= 2.(4 + 2sqrt{3}).2 - 7 - 7sqrt{3} - 14`
`= 16 + 8sqrt{3} - 7 - 7sqrt{3} - 14`
`= sqrt{3} - 5`