Question

Factorise : 3x^2-x-4

Answer 1

Answer:

In the given polynomial 3x

2

−x−4,

The first term is 3x

2

and its coefficient is 3.

The middle term is −x and its coefficient is −1.

The last term is a constant term −4.

Multiply the coefficient of the first term by the constant 3×−4=−12.

We now find the factor of −12 whose sum equals the coefficient of the middle term, which is −1 and then factorize the polynomial 3x

2

−x−4 as shown below:

3x

2

−x−4

=3x

2

+3x−4x−4

=3x(x+1)−4(x+1)

=(3x−4)(x+1)

Hence, 3x

2

−x−4=(3x−4)(x+1).