An equation states that two expressions have the same value. Solving means finding values that keep that balance true.
Use it to expose the allowed unknown value instead of changing one side without preserving equality.
The relationship
Write the rule before calculating
Solve ax + b ◇ 0; reverse the relation when dividing by a negative number.
See the structure
What the calculation is doing
2x − 8=0preserve equality on both sides
Worked interpretation
Read the result in context
Enter the example values shown in the fields to verify the stated relationship.
Interpret with care
Important boundary
An algebraic step is valid only when it applies equally to both sides and does not divide by a possible zero quantity.
Use the Mathematics collection to move between connected concepts without duplicating the calculation.
Understand the subject
What is an inequality?
An inequality describes a range of values rather than requiring exact equality.
Use inequalities for limits, tolerances, budgets, capacity, and any condition expressed as above, below, at least, or at most.
The relationship
The defining equation
if a<0, dividing ax ◇ b by a reverses ◇
The direction reverses because multiplication by a negative number reverses numerical order.
See the structure
Solutions occupy a region of the number line
−3x is to the right: x > −3
Worked example
Solve −2x < 6
x > −3
Interpret with care
What the result does—and does not—mean
Open endpoints exclude equality; closed endpoints include it. Never forget to reverse the sign after multiplying or dividing by a negative value.
Quick guide
How to use this calculator
Enter values using the notation shown beside each field.
Choose a calculation mode when the tool offers more than one interpretation.
Read the primary answer first, then inspect the supporting details.
Calculation method
Apply the stated definition
Solve ax + b ◇ 0; reverse the relation when dividing by a negative number.
The calculator validates the mathematical domain before returning a result and does not replace undefined states with zero.
Worked example
Worked example
Enter the example values shown in the fields to verify the stated relationship.
Solve ax + b ◇ 0; reverse the relation when dividing by a negative number.
Supported inputs
Precision and limits
Finite, bounded input
Numeric inputs use finite JavaScript floating-point values with magnitude limits. Results are normally displayed to 12 significant digits; outputs labelled approximate are not exact identities.
Notation
Enter ordinary finite decimals. Polynomial fields use coefficients in descending powers, separated by commas; for example 1, −3, 2 means x² − 3x + 2.
