A) 2 or 1
B) 3 or 4
C) 5 or 6
D) 7 or 1
Correct Answer: D
Solution :
As obtained by A, we have \[\alpha +\beta =8\] and \[\alpha \beta =12\] \[\therefore \]The equation is \[{{x}^{2}}-8x+12=0\] As obtained by B, we have \[\alpha +\beta =-\,\,8\] and \[\alpha \beta =7\] \[\therefore \]The equation is\[{{x}^{2}}+8x+7=0\] Hence, the correct equation is \[{{x}^{2}}-8x+7=0\] Now, \[{{x}^{2}}-8x+7=0\Rightarrow {{x}^{2}}-7x-x+7=0\] \[\Rightarrow \]\[x(x-7)-1\,\,(x-7)=0\Rightarrow (x-7)(x-1)=0\] \[\Rightarrow \] \[x=7\]or \[x=1\]You need to login to perform this action.
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