From science to arts, IDNLearn.com has the answers to all your questions. Find the answers you need quickly and accurately with help from our knowledgeable and dedicated community members.

What is the solution of [tex]$\frac{x+8}{5x-1} \ \textgreater \ 0$[/tex]?

A. [tex]x \leq -8[/tex] or [tex]x \ \textgreater \ \frac{1}{5}[/tex]
B. [tex]x \ \textless \ -8[/tex] or [tex]x \ \textgreater \ \frac{1}{5}[/tex]
C. [tex]-8 \leq x \ \textless \ \frac{1}{5}[/tex]
D. [tex]-8 \ \textless \ x \ \textless \ \frac{1}{5}[/tex]


Sagot :

To solve the inequality [tex]\(\frac{x+8}{5x-1} > 0\)[/tex], we need to determine the values of [tex]\(x\)[/tex] that make the expression positive. Let's break it down and solve it step-by-step:

1. Identify the critical points:
Firstly, find the points where the numerator and the denominator are zero. These points divide the number line into intervals.

- The numerator [tex]\(x + 8 = 0 \Rightarrow x = -8\)[/tex]
- The denominator [tex]\(5x - 1 = 0 \Rightarrow x = \frac{1}{5}\)[/tex]

2. Intervals to consider:
The critical points divide the [tex]\(x\)[/tex]-axis into three intervals:
[tex]\[ (-\infty, -8), \quad (-8, \frac{1}{5}), \quad (\frac{1}{5}, +\infty) \][/tex]

3. Determine the sign of the expression in each interval:

- For [tex]\(x \in (-\infty, -8)\)[/tex]:
Both the numerator [tex]\(x + 8\)[/tex] and the denominator [tex]\(5x - 1\)[/tex] are negative. A negative divided by a negative is positive.

- For [tex]\(x \in (-8, \frac{1}{5})\)[/tex]:
The numerator [tex]\(x + 8\)[/tex] is positive while the denominator [tex]\(5x - 1\)[/tex] is negative. A positive divided by a negative is negative.

- For [tex]\(x \in (\frac{1}{5}, +\infty)\)[/tex]:
Both the numerator [tex]\(x + 8\)[/tex] and the denominator [tex]\(5x - 1\)[/tex] are positive. A positive divided by a positive is positive.

4. Combine the intervals where the expression is positive:
- We found the expression [tex]\(\frac{x+8}{5x-1} > 0\)[/tex] in the intervals [tex]\((- \infty, -8)\)[/tex] and [tex]\((\frac{1}{5}, + \infty)\)[/tex].

5. Exclude the critical points where the expression is undefined or zero:
- The critical point [tex]\(x = -8\)[/tex] makes the numerator zero, which results in the expression being zero, not positive.
- The critical point [tex]\(x = \frac{1}{5}\)[/tex] makes the denominator zero, which makes the expression undefined.

Thus, the solution of [tex]\(\frac{x+8}{5x-1} > 0\)[/tex] is:
[tex]\[ (-\infty, -8) \cup \left(\frac{1}{5}, +\infty\right) \][/tex]

This corresponds to [tex]\(x < -8\)[/tex] or [tex]\(x > \frac{1}{5}\)[/tex].

Therefore, the correct choice is:
[tex]\[ \boxed{x < -8 \text{ or } x > \frac{1}{5}} \][/tex]