4-1.Complex numbers
hard

यदि $x =  - 5 + 2\sqrt { - 4} ,$ तो ${x^4} + 9{x^3} + 35{x^2} - x + 4$ का मान होगा

A

$160$

B

$- 160$

C

$60$

D

$- 60$

(IIT-1972)

Solution

(b)$x + 5 = 4i$ $⇒ {x^2} + 10x + 25 =  – 16$

अब ${x^4} + 9{x^3} + 35{x^2} – x + 4$

$ = ({x^2} + 10x + 41)({x^2} – x + 4) – 160 =  – 160$

Standard 11
Mathematics

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