The problem asks us to add and simplify the expression $\frac{4}{x+7} + \frac{3}{x^2 - 49}$.

AlgebraAlgebraic FractionsSimplificationFactoringDifference of Squares
2025/4/3

1. Problem Description

The problem asks us to add and simplify the expression 4x+7+3x249\frac{4}{x+7} + \frac{3}{x^2 - 49}.

2. Solution Steps

First, we factor the denominator x249x^2 - 49. This is a difference of squares, so x249=(x7)(x+7)x^2 - 49 = (x-7)(x+7).
Then, we rewrite the expression:
4x+7+3(x7)(x+7)\frac{4}{x+7} + \frac{3}{(x-7)(x+7)}
To add the two fractions, we need a common denominator. The common denominator is (x7)(x+7)(x-7)(x+7).
Multiply the first fraction by x7x7\frac{x-7}{x-7} to get the common denominator:
4x+7x7x7=4(x7)(x7)(x+7)\frac{4}{x+7} \cdot \frac{x-7}{x-7} = \frac{4(x-7)}{(x-7)(x+7)}
Now, the expression becomes:
4(x7)(x7)(x+7)+3(x7)(x+7)\frac{4(x-7)}{(x-7)(x+7)} + \frac{3}{(x-7)(x+7)}
Combine the two fractions:
4(x7)+3(x7)(x+7)\frac{4(x-7) + 3}{(x-7)(x+7)}
Simplify the numerator:
4x28+3(x7)(x+7)\frac{4x - 28 + 3}{(x-7)(x+7)}
4x25(x7)(x+7)\frac{4x - 25}{(x-7)(x+7)}
The denominator is (x7)(x+7)=x249(x-7)(x+7) = x^2 - 49. So, we can write the simplified expression as:
4x25x249\frac{4x - 25}{x^2 - 49}

3. Final Answer

4x25x249\frac{4x-25}{x^2-49}