Sure! Let’s solve each of these
multiplying binomials problems step by step. We’ll use the
distributive property (FOIL method for binomials) — multiply each term in the first binomial by each term in the second binomial, then combine like terms.
---
Problem 1:
(1/3 a²b + 9)(1/3 a²b + 9)
This is a
square of a binomial: `(A + B)² = A² + 2AB + B²`
Let A = `1/3 a²b`, B = `9`
- A² = `(1/3 a²b)² = 1/9 a⁴b²`
- 2AB = `2 * (1/3 a²b) * 9 = 6 a²b`
- B² = `81`
✔ Answer: `1/9 a⁴b² + 6a²b + 81`
---
Problem 2:
(11vw - 2)(2 + 11vw)
Notice this is the same as `(11vw - 2)(11vw + 2)` →
difference of squares: `(A - B)(A + B) = A² - B²`
Let A = `11vw`, B = `2`
- A² = `(11vw)² = 121 v²w²`
- B² = `4`
✔ Answer: `121v²w² - 4`
---
Problem 3:
(20rs - 8tu)(-1 - 4s)
Use distributive property:
Multiply each term in first binomial by each term in second:
- `20rs * (-1) = -20rs`
- `20rs * (-4s) = -80rs²`
- `-8tu * (-1) = 8tu`
- `-8tu * (-4s) = 32stu`
✔ Answer: `-80rs² - 20rs + 32stu + 8tu`
*(Note: Terms are written in standard order — descending powers of variables, but since multi-variable, we can group by variable combinations. No like terms to combine.)*
---
Problem 4:
(-12x³ - 6x²yz)(-6yz - 3x)
Distribute each term:
First term: `-12x³ * (-6yz) = 72x³yz`
Second: `-12x³ * (-3x) = 36x⁴`
Third: `-6x²yz * (-6yz) = 36x²y²z²`
Fourth: `-6x²yz * (-3x) = 18x³yz`
Now combine like terms:
- `72x³yz + 18x³yz = 90x³yz`
- `36x⁴`
- `36x²y²z²`
✔ Answer: `36x⁴ + 90x³yz + 36x²y²z²`
---
Problem 5:
(-21c⁴d⁵ - 7d³)(3c⁴d⁴ - d²)
Distribute:
- `-21c⁴d⁵ * 3c⁴d⁴ = -63c⁸d⁹`
- `-21c⁴d⁵ * (-d²) = 21c⁴d⁷`
- `-7d³ * 3c⁴d⁴ = -21c⁴d⁷`
- `-7d³ * (-d²) = 7d⁵`
Combine like terms:
- `21c⁴d⁷ - 21c⁴d⁷ = 0` → they cancel!
✔ Answer: `-63c⁸d⁹ + 7d⁵`
---
Problem 6:
(m + 10n)(-4n + 2m)
Rewrite second binomial as `(2m - 4n)` for easier multiplication.
Now distribute:
- `m * 2m = 2m²`
- `m * (-4n) = -4mn`
- `10n * 2m = 20mn`
- `10n * (-4n) = -40n²`
Combine like terms:
- `-4mn + 20mn = 16mn`
✔ Answer: `2m² + 16mn - 40n²`
---
Problem 7:
(-2gh + 6)(-gh + 1/2)
Distribute:
- `-2gh * (-gh) = 2g²h²`
- `-2gh * (1/2) = -gh`
- `6 * (-gh) = -6gh`
- `6 * (1/2) = 3`
Combine like terms:
- `-gh - 6gh = -7gh`
✔ Answer: `2g²h² - 7gh + 3`
---
Problem 8:
(-9 + 3p⁶)(p - q⁴)
Distribute:
- `-9 * p = -9p`
- `-9 * (-q⁴) = 9q⁴`
- `3p⁶ * p = 3p⁷`
- `3p⁶ * (-q⁴) = -3p⁶q⁴`
No like terms to combine.
✔ Answer: `3p⁷ - 3p⁶q⁴ - 9p + 9q⁴`
---
##
✔ Final Answers Summary:
1. `1/9 a⁴b² + 6a²b + 81`
2. `121v²w² - 4`
3. `-80rs² - 20rs + 32stu + 8tu`
4. `36x⁴ + 90x³yz + 36x²y²z²`
5. `-63c⁸d⁹ + 7d⁵`
6. `2m² + 16mn - 40n²`
7. `2g²h² - 7gh + 3`
8. `3p⁷ - 3p⁶q⁴ - 9p + 9q⁴`
Let me know if you’d like to see any step broken down further!
Parent Tip: Review the logic above to help your child master the concept of multiplying polynomials worksheet answer key.