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Unfoil Calculator

Reverse FOIL Method:

\[ (a + b)(c + d) = ac + ad + bc + bd \]

e.g., x² + 5x + 6

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1. What is the FOIL Method?

The FOIL method is a technique for multiplying two binomials. FOIL stands for First, Outer, Inner, Last - referring to the terms that are multiplied together.

2. How to Reverse FOIL

Reversing FOIL means factoring a quadratic expression back into two binomials. For example:

\[ x² + 5x + 6 = (x + 2)(x + 3) \]

This is done by finding two numbers that:

3. Steps to Factor Quadratic Expressions

Step 1: Write the expression in standard form (ax² + bx + c)
Step 2: Find two numbers that multiply to ac and add to b
Step 3: Rewrite the middle term using these numbers
Step 4: Factor by grouping
Step 5: Write as product of two binomials

4. Using the Calculator

Tips: Enter your quadratic expression in expanded form (e.g., x² + 5x + 6). The calculator will attempt to factor it back into binomials.

5. Frequently Asked Questions (FAQ)

Q1: What if the expression can't be factored?
A: Some quadratic expressions are prime and cannot be factored into simpler binomials with integer coefficients.

Q2: How do you handle expressions with a leading coefficient?
A: For expressions like 2x² + 5x + 3, you need to consider the product of the leading coefficient and constant term (2×3=6) when finding factors.

Q3: What's the difference between factoring and FOIL?
A: FOIL is the multiplication process, while factoring is the reverse - breaking the expanded form back into multiplied binomials.

Q4: Can this calculator factor perfect square trinomials?
A: Yes, expressions like x² + 6x + 9 will factor to (x + 3)².

Q5: What about difference of squares?
A: Expressions like x² - 9 factor to (x + 3)(x - 3).

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