Question

factories -:3x²-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).

Step-by-step explanation:

Answer 2

Step-by-step explanation:

$= 3 {x}^{2} - x - 4 \\ = 3 {x}^{2} - (4 - 3)x - 4 \\ = 3 {x}^{2} - 4x + 3x - 4 \\ = x(3x - 4) + 1(3x - 4) \\ = (3x - 4)(x +1)$