A) ± 1
B) ± 2
C) ± 3
D) ± 4
Correct Answer: B
Solution :
Let\[\alpha \]be the common root of given equations, therefore \[{{\alpha }^{2}}+7a\alpha +40=0\] ? (i) and \[{{\alpha }^{2}}+2a\alpha -60=0\] ? (ii) Subtracting equation (ii) from (i), we get \[5a\alpha +100=0\] or \[a\alpha =0\] ? (iii) Substituting for \[a\alpha \] in equation (ii), we get \[{{\alpha }^{2}}-40-60=0\] or \[\alpha =\pm 10\] \[\therefore \] \[a=\pm 2\]
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