A) 45
B) 15
C) \[-15\]
D) \[-45\]
E) 25
Correct Answer: A
Solution :
If one root is\[2-i,\]then the other root will be \[2+i.\] Given equation is\[a{{x}^{2}}+12x+b=0\] \[\therefore \] \[2-i+2+i=\frac{-12}{a}\] \[\Rightarrow \] \[a=-3\] and \[(2-i)(2+i)=\frac{b}{a}\] \[\Rightarrow \] \[5=\frac{b}{-3}\Rightarrow b=-15\] \[\therefore \] \[ab=-3\times (-15)=45\]You need to login to perform this action.
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