Question

If x = – 5 + 2$\sqrt{–4}$then the value of the expression x⁴ + 9x³ + 35x² – x + 4 is equal to –

• A. 160
• B. – 160
• C. 120
• D. – 120

Answer 1

Answer: (B)

– 160

Answer 2

(x + 5)² = (4i)² Ž x² + 10x + 41 = 0

Now, x⁴ + 9x³ + 35x² – x + 4

= x² (x² + 10x + 41) – x (x² + 10x + 41) + 4(x² + 10x + 41) – 160

= (x² – x + 4) (x² + 10 x + 41) – 160

= – 160