Question

Please help me factor.
49 - 9x²

Answer 1

Answer: -(3x - 7)(3x + 7)

Explanation:

1. Rewrite the formula:

-
`9x^(2) + 49`

2. Factor -1 out of
`-9x^(2) + 49`

`-(9x^(2) - 49)`

3.
`9x^(2) - 49 = (3x)^(2) - 7^(2)`

`((3x)^(2) - 7^(2))`

4. Factor the difference of two squares.
`(3x)^(2) - 7^(2) =`

`(3x-7)(3x+7)`

5. Add back negative:

Answer:
`-(3x-7)(3x+7)`

Answer 2

a

2

−

b

2

=

(

a

+

b

)

(

a

−

b

)

where

a

=

7

and

b

=

3

x

.

(

7

+

3

x

)

(

7

−

3

x

)