Question

LaTeX: \frac{x}{x+5}=\frac{50}{x^2-25}+6

Answers

GPT-4o mini
To solve the equation

\[
\frac{x}{x+5} = \frac{50}{x^2 - 25} + 6,
\]

we start by noticing that \(x^2 - 25\) is a difference of squares and can be factored as

\[
x^2 - 25 = (x - 5)(x + 5).
\]

This means we can rewrite the equation as:

\[
\frac{x}{x + 5} = \frac{50}{(x - 5)(x + 5)} + 6.
\]

To eliminate the fractions, we can multiply both sides of the equation by \((x - 5)(x + 5)\):

\[
x(x - 5) = 50 + 6(x - 5)(x + 5).
\]

Now we distribute on the right side:

\[
x(x - 5) = 50 + 6(x^2 - 25).
\]

This simplifies to:

\[
x^2 - 5x = 50 + 6x^2 - 150.
\]

Combining like terms on the right side gives:

\[
x^2 - 5x = 6x^2 - 100.
\]

Next, we move all terms to one side of the equation:

\[
x^2 - 5x - 6x^2 + 100 = 0,
\]

which simplifies to:

\[
-5x^2 - 5x + 100 = 0.
\]

We can divide the whole equation by -5:

\[
x^2 + x - 20 = 0.
\]

Now, we can factor this quadratic:

\[
(x + 5)(x - 4) = 0.
\]

Setting each factor equal to zero gives us:

\[
x + 5 = 0 \quad \Rightarrow \quad x = -5,
\]
\[
x - 4 = 0 \quad \Rightarrow \quad x = 4.
\]

Now we check if these values lead to any restrictions due to the original equation's denominators.

Substituting back into the denominators:
- For \(x = -5\), the expression \(\frac{x}{x + 5}\) becomes undefined, so \(x = -5\) is not valid.
- For \(x = 4\), it's valid since \(x + 5 \neq 0\) and \(x - 5 \neq 0\).

Thus, the only valid solution is

\[
\boxed{4}.
\]