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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