The FOIL method for multiplying polynomials
Lesson 14 of 20 in Union Aptitude Prep. The start plays free here.
- x + 5
- 3(x + 5)(x − 2)
- 3(x + 5)(x − 2)
- = 3(x² − 2x + 5x − 10)
- = 3(x² + 3x − 10)
- = 3x² + 9x − 30
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How the lesson starts
A polynomial is an expression made of terms, such as x + 5. Here, x and 5 are the terms.
An official aptitude sample asks you to multiply polynomials like these. You need to recognize the result even when it looks different from the starting expression.
You see x + 5 in an expression. Its two terms make it a binomial. A monomial has one term. A trinomial has three.
Then, in the full lesson
- Like terms
- Four products
- Combine carefully
- Equivalent expressions
- 2 questions along the way
A question from this lesson
You simplify 4x² + 2x + 3x². Which expression matches?
- 4x² + 5x
- 9x²
- 7x² + 2x
Show the answer
C. 7x² + 2x. 7x² + 2x combines the two x² terms. The x term stays separate. 9x² combines unlike terms. 4x² + 5x incorrectly combines 2x with 3x².
The full class, $39 once.
Paid once, no subscription. Ask for a refund within 7 days of buying if you’ve done less than 25% of the class.
- Number series trainer
- Algebra & functions with worked steps
- Reading comprehension sets
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