Perfect Square Trinomial Calculator

Check if a trinomial is a perfect square and find its factorization

Enter Trinomial Coefficients

Your Trinomial

x² + 4x + 4

Coefficient of x²

Coefficient of x

Constant term

Analysis Results

Perfect Square Status

✓ YES

This is a perfect square trinomial

Discriminant (Δ)

0

Δ = b² - 4ac

Factorization

x² + 4x + 4 = (x + 2)²

Step-by-Step Solution

1

Given trinomial: x² + 4x + 4

2

Calculate discriminant: Δ = b² - 4ac = 4² - 4(1)(4) = 16 - 16 = 0

3

Since Δ = 0, this trinomial IS a perfect square!

4

Compute square roots: √|a| = √1 = 1, √|c| = √4 = 2

5

Since a ≥ 0 and b ≥ 0, use form (x√|a| + √|c|)²

6

Factorization: (x + 2)²

7

Verification: Expand (x + 2)² to check if it equals x² + 4x + 4

Quick Examples

Perfect Square Rules

1

Check Discriminant

Δ = b² - 4ac must equal 0

2

Find Square Roots

Calculate √|a| and √|c|

3

Determine Signs

Check signs of a and b coefficients

4

Apply Formula

Use appropriate binomial form

Formula Reference

Perfect Square Forms

(px + q)² = p²x² + 2pqx + q²
(px - q)² = p²x² - 2pqx + q²

Discriminant Test

Δ = b² - 4ac = 0

Sign Rules

• a ≥ 0, b ≥ 0: (x√|a| + √|c|)²
• a < 0, b < 0: -(x√|a| + √|c|)²
• a ≥ 0, b < 0: (x√|a| - √|c|)²
• a < 0, b > 0: -(x√|a| - √|c|)²

Understanding Perfect Square Trinomials

What is a Perfect Square Trinomial?

A perfect square trinomial is a quadratic expression that can be written as the square of a binomial. In other words, it's a trinomial of the form ax² + bx + c that can be factored as (px + q)² or (px - q)².

Why Use the Discriminant?

  • The discriminant Δ = b² - 4ac determines the nature of roots
  • When Δ = 0, there's exactly one repeated root
  • This means the trinomial can be written as a perfect square
  • If Δ ≠ 0, the trinomial cannot be a perfect square

Step-by-Step Process

Step 1: Calculate Discriminant

Compute Δ = b² - 4ac. If Δ ≠ 0, stop here—it's not a perfect square.

Step 2: Find Square Roots

Calculate √|a| and √|c| to determine the binomial coefficients.

Step 3: Apply Sign Rules

Use the signs of a and b to determine which formula to apply.

Step 4: Verify Result

Expand your factorization to confirm it equals the original trinomial.

Worked Examples

Example 1: x² + 4x + 4

Step 1: Δ = 4² - 4(1)(4) = 16 - 16 = 0 ✓
Step 2: √|1| = 1, √|4| = 2
Step 3: a > 0, b > 0 → (x + 2)²
Result: x² + 4x + 4 = (x + 2)²

Example 2: x² - 6x + 9

Step 1: Δ = (-6)² - 4(1)(9) = 36 - 36 = 0 ✓
Step 2: √|1| = 1, √|9| = 3
Step 3: a > 0, b < 0 → (x - 3)²
Result: x² - 6x + 9 = (x - 3)²

Example 3: 4x² + 12x + 9

Step 1: Δ = 12² - 4(4)(9) = 144 - 144 = 0 ✓
Step 2: √|4| = 2, √|9| = 3
Step 3: a > 0, b > 0 → (2x + 3)²
Result: 4x² + 12x + 9 = (2x + 3)²

Example 4: x² + 2x + 2

Step 1: Δ = 2² - 4(1)(2) = 4 - 8 = -4 ✗
Result: Not a perfect square (Δ ≠ 0)