Absolute Value Inequalities Calculator

Solve |ax + b| < c or |ax + b| > c.

Lower boundary -3
Upper boundary 7
Solution (-3, 7)

Formula: < gives a sandwich; > gives a union

Step-by-step with your numbers:
1. Values used:
2. a = 1
3. b = -2
4. c = 5
5.
6. Lower boundary = -3
7. Upper boundary = 7
8. Solution = (-3, 7)
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Absolute-value inequalities split into two cases that give either a single interval or a union.

How the Math Works

The Absolute Value Inequalities Calculator solves expressions of the form |ax + b| < c or |ax + b| > c by converting them into compound inequalities. For |ax + b| < c, the solution is a 'sandwich' inequality: -c < ax + b < c, representing all x-values between two bounds. Conversely, |ax + b| > c splits into a union of two inequalities: ax + b > c or ax + b < -c, capturing x-values outside the interval [-c, c]. This transformation relies on the definition of absolute value as distance from zero, enabling the calculator to handle both bounded and unbounded solution sets efficiently.

Practical Applications

This calculation is essential in fields like engineering, economics, and physics where constraints must be satisfied within specific tolerances. For instance, in manufacturing, determining if a product’s dimensions fall within acceptable limits (e.g., |measured value - target| < tolerance) ensures quality control. In optimization problems, such inequalities define feasible regions for variables, guiding decisions like resource allocation or route planning. The calculator simplifies these processes by quickly deriving valid ranges for x, allowing professionals to focus on higher-level problem-solving rather than manual inequality manipulation.

Day-to-Day Use

In everyday scenarios, absolute value inequalities help manage uncertainties and tolerances. For example, when budgeting, you might calculate if your expenses stay within 10% of your monthly income using |expenses - income| < 0.1 * income. Similarly, in cooking, adjusting recipe ingredients within a margin of error (e.g., |actual amount - desired amount| < 0.5 cups) ensures consistent results. The calculator aids in making quick, informed decisions by quantifying acceptable deviations from target values, whether in personal finance, health goals, or time management tasks.

Worked example

|x − 2| < 5 → −3 < x < 7, i.e. (−3, 7).

FAQ

What if c is negative?

For '<' there is no solution; for '>' all real numbers work.