Question

5x2-3x-8 how to use Ac method
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Answer 1

`(x+1)(5x-8)`

Explanation:

1) Split the second term in
`5x^2-3x-8` into two terms.

1 - Multiply the coefficient of the first term by the constant term.

`5*-8=-40`

2 - Ask: Which two numbers add up to
`-3` and multiply to
`-40`?

`5` and
`-8`

3 - Split
`-3x` as the sum of
`5x` and
`-8x`.

`5x^2+5x-8x-8`

2) Factor out common terms in the first two terms, then in the last two terms.

`5x(x+1)-8(x+1)`

3) Factor out the common term
`x+1`.

`(x+1)(5x-8)`