Q6 of 108 Page 46

If x = 1 is a common root of the equations ax2 + ax + 3 = 0 and x2 + x + b = 0 then the value of ab will be:

Put x = 1 in the first equation,

a + a + 3 = 0


2a = -3


a = -3/2


Put x = 1 in the second equation,


1 + 1 + b = 0


b + 2 = 0


b = -2


Therefore the value of ab = -3/2 × -2


= 3


So the correct answer is D [3].

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