Respuesta :

ktreyb
First, you factor and simplify (respectively) the numerator and denominator. Your equation becomes:

[tex] \frac{(x-7)(x+7)}{3(x + 7)} [/tex]

Notice, there is a (x + 7) on both the top and the bottom. Because of this, they cancel each other out. What is left is your answer:

[tex] \frac{(x-7)}{3} [/tex]

The simplified expression of [tex]\mathbf{\frac{x^2 - 49}{3x + 21} }[/tex] is [tex]\mathbf{\frac{x - 7}{3}}[/tex]

The expression is given as:

[tex]\mathbf{\frac{x^2 - 49}{3x + 21}}[/tex]

Express 49 as 7^2

[tex]\mathbf{\frac{x^2 - 49}{3x + 21} = \frac{x^2 - 7^2}{3x + 21}}[/tex]

Express x^2 - 7^2 as difference of two squares

[tex]\mathbf{\frac{x^2 - 49}{3x + 21} = \frac{(x - 7)(x + 7)}{3x + 21}}[/tex]

Factor out 3

[tex]\mathbf{\frac{x^2 - 49}{3x + 21} = \frac{(x - 7)(x + 7)}{3(x + 7)}}[/tex]

Cancel out common factor: x + 7

[tex]\mathbf{\frac{x^2 - 49}{3x + 21} = \frac{x - 7}{3}}[/tex]

Hence, the simplified expression of [tex]\mathbf{\frac{x^2 - 49}{3x + 21} }[/tex] is [tex]\mathbf{\frac{x - 7}{3}}[/tex]

Read more about simplifying expressions at:

https://brainly.com/question/23832524

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