Question

The product of some negative number and 4 less than twice that number is 336. Find the number.

Answer 1

Let the number be 'x'

Since, the product of number and 4 less than twice that number is 336.

`x * [(2 * x) -4] = 336`

`x[2x -4] = 336`

`2x^2 -4x- 336=0`

`x^2-2x-168=0`

Now, we will split the middle term, we get

`x^2-14x+12x-168=0`

`x(x-14)+12(x-14)=0`

`(x-14)(x+12)=0`

So,
`(x-14)=0 or (x+12)=0`

So, x = 14 or x = -12

Therefore, the negative number is '-12'.