Q1 of 157 Page 30

Choose the correct answer for the following:

The factors of x2 – x – 12 are ______

Given x2 – x – 12


Using (x + a)(x + b) = x2 + (a + b)x + ab … (I)


⇒ x2 – x – 12 = x2 + ( – 4 + 3)x + ( – 4)×3


On comparing with (I),


a = – 4 and b = 3


So, x2 – x – 12 = (x – 4)(x + 3)


The factors of x2 – x – 12 are (x – 4) and (x + 3)

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