Solution of Compound Inequality

Problem:
We are solving a compound inequality of the form: $$ a < bx + c < d $$

Steps of solution:

  1. Step 1: Isolate the term with 𝑥 by subtracting 𝑐 from all parts: $$ a − c < bx < d − c $$ This step ensures that 𝑥 is on its own term.
  2. Step 2: Divide all parts of the inequality by 𝑏 to isolate 𝑥: $$ \frac{a - c}{b} < x < \frac{d - c}{b} $$ Now 𝑥 is isolated and the inequality is solved.
  3. Final Step: Write the solution set in interval notation: The solution set is written as: $$ (\frac{a - c}{b}, \frac{d - c}{b}) $$

Example:

Solution: