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
ax + b = 0 ⇒ x = −b/a
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 a linear equation?
A one-variable linear equation has the variable only to the first power. Its graph is a straight line, and solving finds where that line reaches zero.
Linear equations model constant-rate relationships, fixed plus variable costs, and direct changes.
The relationship
The defining equation
ax+b=0 ⇒ x=−b/a
a is the nonzero coefficient of x and b is the constant term.
See the structure
Undo the constant, then the coefficient
2x − 80Do the same operation to both sides
Worked example
Solve 3x − 12 = 0
x = −(−12)/3 = 4
Interpret with care
What the result does—and does not—mean
If a=0, the expression is not a one-variable linear equation: it is either always true or impossible depending on b.
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
ax + b = 0 ⇒ x = −b/a
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.
ax + b = 0 ⇒ x = −b/a
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.
