Let's solve each problem step by step. These are
special cases of binomial multiplication, specifically
squaring a binomial.
The formula for squaring a binomial is:
$$
(a + b)^2 = a^2 + 2ab + b^2
$$
or
$$
(a - b)^2 = a^2 - 2ab + b^2
$$
We can also use the distributive property (FOIL) to expand:
(First, Outer, Inner, Last)
But since these are squares, we'll use the pattern:
$$
(A + B)^2 = A^2 + 2AB + B^2
$$
Let’s go through each one.
---
1. $(-3k - 4)^2$
This is of the form $(a + b)^2$, where $a = -3k$, $b = -4$
$$
(-3k - 4)^2 = (-3k)^2 + 2(-3k)(-4) + (-4)^2
$$
$$
= 9k^2 + 24k + 16
$$
✔ Answer: $9k^2 + 24k + 16$
---
2. $(-2y - 1)^2$
$a = -2y$, $b = -1$
$$
(-2y - 1)^2 = (-2y)^2 + 2(-2y)(-1) + (-1)^2
$$
$$
= 4y^2 + 4y + 1
$$
✔ Answer: $4y^2 + 4y + 1$
---
3. $(-3a - 5)^2$
$a = -3a$, $b = -5$
$$
(-3a - 5)^2 = (-3a)^2 + 2(-3a)(-5) + (-5)^2
$$
$$
= 9a^2 + 30a + 25
$$
✔ Answer: $9a^2 + 30a + 25$
---
4. $(n + 3)^2$
$a = n$, $b = 3$
$$
(n + 3)^2 = n^2 + 2(n)(3) + 3^2 = n^2 + 6n + 9
$$
✔ Answer: $n^2 + 6n + 9$
---
5. $(-2c + 1)^2$
This is $(-2c + 1)^2$, so $a = -2c$, $b = 1$
$$
(-2c + 1)^2 = (-2c)^2 + 2(-2c)(1) + (1)^2
$$
$$
= 4c^2 - 4c + 1
$$
✔ Answer: $4c^2 - 4c + 1$
---
6. $(-c + 2)^2$
$a = -c$, $b = 2$
$$
(-c + 2)^2 = (-c)^2 + 2(-c)(2) + (2)^2
$$
$$
= c^2 - 4c + 4
$$
✔ Answer: $c^2 - 4c + 4$
---
7. $(-c + 1)^2$
$a = -c$, $b = 1$
$$
(-c + 1)^2 = (-c)^2 + 2(-c)(1) + (1)^2
$$
$$
= c^2 - 2c + 1
$$
✔ Answer: $c^2 - 2c + 1$
---
8. $(2b - 5)^2$
$a = 2b$, $b = -5$
$$
(2b - 5)^2 = (2b)^2 + 2(2b)(-5) + (-5)^2
$$
$$
= 4b^2 - 20b + 25
$$
✔ Answer: $4b^2 - 20b + 25$
---
✔ Final Answers:
| Problem | Answer |
|--------|--------|
| 1. $(-3k - 4)^2$ | $9k^2 + 24k + 16$ |
| 2. $(-2y - 1)^2$ | $4y^2 + 4y + 1$ |
| 3. $(-3a - 5)^2$ | $9a^2 + 30a + 25$ |
| 4. $(n + 3)^2$ | $n^2 + 6n + 9$ |
| 5. $(-2c + 1)^2$ | $4c^2 - 4c + 1$ |
| 6. $(-c + 2)^2$ | $c^2 - 4c + 4$ |
| 7. $(-c + 1)^2$ | $c^2 - 2c + 1$ |
| 8. $(2b - 5)^2$ | $4b^2 - 20b + 25$ |
---
🔍 Key Concept:
When squaring a binomial $(A + B)^2$, always remember:
- Square the first term
- Twice the product of both terms
- Square the last term
And
pay attention to signs, especially when negative numbers are involved.
Let me know if you'd like this in a printable format or with more explanation!
Parent Tip: Review the logic above to help your child master the concept of multiplying special case polynomials worksheet.