Question

In the equation 6x^2+7x-49 how does 7x become -14x and 21x?

Answer 1

See the explanation.

Explanation:

Given function is
`6x^2+7x-49`

We will find its root by factoring.

In any quadratic function of the form
`ax^2+bx+c`

We will two numbers that when multiplied gives
`ac`. And when that two numbers are added it turns to
`b`.

So, in
`6x^2+7x-49`.

`a=6,\ b=7.\ c=-49`

And
`ac=-294`

So, we need to find two numbers that when multiplied give
`-294`,and when added give
`7`.

Now, we can see

`-14*21=-294\\And\ -14+21=7`

In this manner, we can rewrite
`7x` as
`-14x+21x`.