Question

factorise of :2x²-x-1​

Answer 1

Answer:

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

Answer 2

Given,

• 2x²-x-1​ is given.

To find,

• We have to find the factors of 2x²-x-1​.

Solution,

We can simply find the factors of 2x²-x-1​ by using the method of splitting the middle terms.

                  = 2x²-x-1​

                   = 2x² -(2-1)x-1

                   = 2x²-2x+x-1

Taking 2x common from the first two terms and 1 common from the last two terms, we get

                   = 2x(x-1)+1(x-1)

Taking (x-1) common, we get

                   = (x-1)(2x+1)

Hence, the factors of 2x²-x-1​ are (x-1)(2x+1).