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Square of a Binomial Calculator.

Expand (a + b)² using the binomial identity.

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Set your values

Results update as you type.

Result: result: 25.00000000

Result

result: 25.00000000

Use Cases

Algebra Homework Help

Quickly verify your manual expansion of squared binomials, ensuring accuracy in your algebra assignments.

Example: Check that (x + 3)^2 expands to x^2 + 6x + 9.

Simplifying Expressions

Use the calculator to simplify expressions that involve squaring a binomial, saving time in more complex calculations.

Example: Simplify (2a - 5)^2 to 4a^2 - 20a + 25.

Frequently Asked Questions

What does the Square of a Binomial Calculator do?
It expands a binomial squared, such as (a + b)^2 or (a - b)^2, into its polynomial form. You enter the values for a and b, and the calculator shows the expanded expression.
How do I use the calculator?
Simply enter the values for a and b in the input fields. The calculator will compute the square of the binomial and display the expanded form, following the formula (a ± b)^2 = a^2 ± 2ab + b^2.
Can I use this calculator for negative numbers?
Yes, you can enter negative values for a and b. The calculator will handle the signs correctly and produce the expanded form, which may include negative coefficients.

Tips & Common Mistakes

Tips

  • Remember the formula: (a + b)^2 = a^2 + 2ab + b^2, and (a - b)^2 = a^2 - 2ab + b^2.
  • Double-check your input values for a and b to avoid errors in the expansion.
  • Use the calculator to practice and confirm your understanding of binomial expansion.
  • If you have a binomial like (2x + 3)^2, enter a = 2x and b = 3, but note that the calculator expects numeric values, so you may need to substitute variables with numbers.

Common Mistakes to Avoid

  • Forgetting the middle term: many users incorrectly write (a + b)^2 as a^2 + b^2, omitting the 2ab term.
  • Misapplying signs: when expanding (a - b)^2, some forget the negative sign in the middle term, writing a^2 + 2ab + b^2 instead of a^2 - 2ab + b^2.
  • Entering variables instead of numbers: the calculator expects numeric values for a and b, so entering algebraic expressions like 'x' will not work.

Last updated: August 13, 2026