Which expression is equivalent to [tex]\frac{2n}{n+4} + \frac{7}{n-1}[/tex] if no denominator equals zero?

A. [tex]\frac{2n^2 + 5n + 28}{(n+4)(n-1)}[/tex]

B. [tex]\frac{2n^2 + 5n + 4}{(n+4)(n-1)}[/tex]

C. [tex]\frac{2n^2 + 6n + 28}{(n+4)(n-1)}[/tex]

D. [tex]\frac{2n^2 + 6n + 4}{(n+4)(n-1)}[/tex]



Answer :

To simplify the expression [tex]\(\frac{2n}{n+4} + \frac{7}{n-1}\)[/tex], we need to find a common denominator. The common denominator for the fractions is [tex]\((n+4)(n-1)\)[/tex].

1. Rewrite each fraction with the common denominator:

[tex]\[ \frac{2n}{n+4} = \frac{2n(n-1)}{(n+4)(n-1)} \][/tex]

[tex]\[ \frac{7}{n-1} = \frac{7(n+4)}{(n+4)(n-1)} \][/tex]

2. Add the two fractions:

[tex]\[ \frac{2n(n-1)}{(n+4)(n-1)} + \frac{7(n+4)}{(n+4)(n-1)} = \frac{2n(n-1) + 7(n+4)}{(n+4)(n-1)} \][/tex]

3. Expand the numerators:

[tex]\[ 2n(n-1) = 2n^2 - 2n \][/tex]

[tex]\[ 7(n+4) = 7n + 28 \][/tex]

4. Combine the expanded numerators:

[tex]\[ 2n^2 - 2n + 7n + 28 = 2n^2 + 5n + 28 \][/tex]

5. Combine the fractions:

[tex]\[ \frac{2n^2 + 5n + 28}{(n+4)(n-1)} \][/tex]

Thus, the expression [tex]\(\frac{2n}{n+4} + \frac{7}{n-1}\)[/tex] simplifies to [tex]\(\frac{2n^2 + 5n + 28}{(n+4)(n-1)}\)[/tex].

The correct answer is:

A. [tex]\(\frac{2n^2 + 5n + 28}{(n+4)(n-1)}\)[/tex]