Question
Question: If (*x*) = *x*<sup>4</sup> + 9*x*<sup>3</sup> + 35*x*<sup>2</sup> – *x* + 4, then (– 5 + 2 \(\sqr...
If (x) = x4 + 9x3 + 35x2 – x + 4, then (– 5 + 2 −4) is equal to –
A
– 160
B
160
C
0
D
None of thes
Answer
– 160
Explanation
Solution
Let, y = – 5 + 4i ⇒ y2 + 10y + 41 = 0
∴ x) = x4 + 9x3 + 35x2 – x + 4
= x2 (x2 + 10x + 41) – x(x2 + 10x + 41) + 4(x2 + 10x + 41) – 160
= – 160
∴ (– 5 + 4i) = – 160