Tutor guide · Free tools
How to check a linear equation
First collect like terms yourself. Enter the four numerical coefficients, then compare the transformation and substitution with your working.
For tutors and learners who already know how to collect like terms; the MomentDesk account is for learners aged 14 and over.
What to do
Prepare the equation
Collect like terms on each side to obtain ax+b=cx+d. Keep your original equation and your working: the tool cannot verify the expansion or model for you.
Enter four coefficients
Enter a, b, c and d, including their signs. Use 0 for an absent x-term or constant. Enter a number, not the letter or a full expression.
Choose notation and domain
Choose ℚ or ℝ and a dot or comma for display independently of the page language. Resolve an ambiguous separator separately for each affected field.
Read the classification
Calculate. Compare (a−c)x=d−b with your own steps. A nonzero x-coefficient gives one solution; a zero coefficient gives either an impossible equality or an identity.
Test your own value
Optionally enter your candidate x. Compare both substituted sides exactly. This test does not verify the explanation, units or all values in an identity.
Use the working in a lesson
Copy the text or print the working to PDF, then attach it to a lesson or homework if needed. Use the linked explanations and practice to work independently. Editing a coefficient requires a new calculation.
Good to know
- Enter integers, decimals with a dot or comma, ordinary fractions such as 3/4, or mixed numbers such as −1 1/2. Each numerical part may contain at most 12 digits. Do not enter x, brackets or other expressions in the fields.
- This tool checks numerical coefficients in ax + b = cx + d. It does not check how you expanded brackets, formed a word-problem model, chose units or met a course requirement. A successful substitution alone does not prove your reasoning. Coefficients and candidate values must be rational; ℝ also includes irrational solutions in an identity.
- All coefficients and working stay in this browser tab. They are not sent to AI, stored in your account or placed in the page URL.
- Copied text uses a/b for fractions; the screen and PDF show vertical fractions. The result is exact and is not silently rounded.