Absolutely! Let’s solve each of these binomial multiplication problems using the
FOIL method.
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📌 What is FOIL?
FOIL stands for:
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First → Multiply the first terms in each binomial
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Outer → Multiply the outer terms
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Inner → Multiply the inner terms
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Last → Multiply the last terms
Then, combine like terms to simplify.
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Let’s go one by one:
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1. `(x + 2)(2x + 5)`
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F: `x * 2x = 2x²`
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O: `x * 5 = 5x`
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I: `2 * 2x = 4x`
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L: `2 * 5 = 10`
→ Combine: `2x² + 5x + 4x + 10 = 2x² + 9x + 10`
✔ Answer: `2x² + 9x + 10`
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2. `(3x - 3)(x + 3)`
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F: `3x * x = 3x²`
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O: `3x * 3 = 9x`
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I: `-3 * x = -3x`
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L: `-3 * 3 = -9`
→ Combine: `3x² + 9x - 3x - 9 = 3x² + 6x - 9`
✔ Answer: `3x² + 6x - 9`
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3. `(4a - 5)(a + 3)`
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F: `4a * a = 4a²`
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O: `4a * 3 = 12a`
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I: `-5 * a = -5a`
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L: `-5 * 3 = -15`
→ Combine: `4a² + 12a - 5a - 15 = 4a² + 7a - 15`
✔ Answer: `4a² + 7a - 15`
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4. `(2a + 1)(a + 3)`
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F: `2a * a = 2a²`
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O: `2a * 3 = 6a`
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I: `1 * a = a`
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L: `1 * 3 = 3`
→ Combine: `2a² + 6a + a + 3 = 2a² + 7a + 3`
✔ Answer: `2a² + 7a + 3`
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5. `(2x + 7)(x - 8)`
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F: `2x * x = 2x²`
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O: `2x * (-8) = -16x`
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I: `7 * x = 7x`
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L: `7 * (-8) = -56`
→ Combine: `2x² - 16x + 7x - 56 = 2x² - 9x - 56`
✔ Answer: `2x² - 9x - 56`
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6. `(x + 2)²`
This is the same as `(x + 2)(x + 2)` — so we apply FOIL.
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F: `x * x = x²`
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O: `x * 2 = 2x`
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I: `2 * x = 2x`
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L: `2 * 2 = 4`
→ Combine: `x² + 2x + 2x + 4 = x² + 4x + 4`
✔ Answer: `x² + 4x + 4`
*(Note: This is also a perfect square trinomial: `(a + b)² = a² + 2ab + b²`)*
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7. `(3x + 1)(2x + 6)`
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F: `3x * 2x = 6x²`
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O: `3x * 6 = 18x`
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I: `1 * 2x = 2x`
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L: `1 * 6 = 6`
→ Combine: `6x² + 18x + 2x + 6 = 6x² + 20x + 6`
✔ Answer: `6x² + 20x + 6`
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8. `(a - 5)²`
Same as `(a - 5)(a - 5)`
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F: `a * a = a²`
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O: `a * (-5) = -5a`
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I: `-5 * a = -5a`
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L: `-5 * (-5) = 25`
→ Combine: `a² - 5a - 5a + 25 = a² - 10a + 25`
✔ Answer: `a² - 10a + 25`
*(Perfect square trinomial: `(a - b)² = a² - 2ab + b²`)*
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##
✔ Final Answers Summary:
1. `(x + 2)(2x + 5)` =
`2x² + 9x + 10`
2. `(3x - 3)(x + 3)` =
`3x² + 6x - 9`
3. `(4a - 5)(a + 3)` =
`4a² + 7a - 15`
4. `(2a + 1)(a + 3)` =
`2a² + 7a + 3`
5. `(2x + 7)(x - 8)` =
`2x² - 9x - 56`
6. `(x + 2)²` =
`x² + 4x + 4`
7. `(3x + 1)(2x + 6)` =
`6x² + 20x + 6`
8. `(a - 5)²` =
`a² - 10a + 25`
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Let me know if you’d like to see any of these with step-by-step diagrams or video-style explanations! 😊
Parent Tip: Review the logic above to help your child master the concept of using foil worksheet.