Let's solve each problem step by step using the
Remainder Theorem and
Factor Theorem.
---
🔷 Remainder Theorem:
When a polynomial $ P(x) $ is divided by $ x - c $, the remainder is $ P(c) $.
🔷 Factor Theorem:
If $ P(c) = 0 $, then $ x - c $ is a factor of $ P(x) $.
So if the remainder $ R = 0 $, then the divisor
is a factor. Otherwise, it is
not.
---
##
✔ Problem 1:
Divide $ x^4 + 4x^3 - 11x - 5 $ by $ x + 3 $
We use $ P(-3) $ because $ x + 3 = x - (-3) $, so $ c = -3 $
Given:
$$
P(-3) = (-3)^4 + 4(-3)^3 - 11(-3) - 5
$$
$$
= 81 + 4(-27) + 33 - 5
$$
$$
= 81 - 108 + 33 - 5
$$
$$
= (81 + 33) - (108 + 5) = 114 - 113 = 1
$$
✔ So, $ P(-3) = R = \boxed{1} $
Since remainder ≠ 0 →
Not a factor
👉
Answer:
- $ P(-3) = R = \boxed{1} $
- Is it a factor? →
No
---
##
✔ Problem 2:
Divide $ x^3 + 5x^2 - 2x - 24 $ by $ x - 2 $
Use $ P(2) $ because $ x - 2 $ → $ c = 2 $
$$
P(2) = (2)^3 + 5(2)^2 - 2(2) - 24
$$
$$
= 8 + 5(4) - 4 - 24
$$
$$
= 8 + 20 - 4 - 24
$$
$$
= 28 - 28 = 0
$$
✔ So, $ P(2) = R = \boxed{0} $
Since remainder = 0 →
It is a factor
👉
Answer:
- $ P(2) = \boxed{0} $
- Is it a factor? →
Yes
---
##
✔ Problem 3:
Divide $ 4x^3 - 12x^2 - x + 3 $ by $ x - 3 $
Use $ P(3) $ because $ x - 3 $ → $ c = 3 $
$$
P(3) = 4(3)^3 - 12(3)^2 - (3) + 3
$$
$$
= 4(27) - 12(9) - 3 + 3
$$
$$
= 108 - 108 - 3 + 3
$$
$$
= 0 + 0 = 0
$$
✔ So, $ P(3) = R = \boxed{0} $
Since remainder = 0 →
It is a factor
👉
Answer:
- $ P(3) = 4(27) - 12(9) - 3 + 3 = 108 - 108 - 3 + 3 = 0 $
- $ P(3) = R = \boxed{0} $
- Is it a factor? →
Yes
---
✔ Final Answers:
#### 1.
$ P(-3) = R = \boxed{1} $ →
No, not a factor
#### 2.
$ P(2) = \boxed{0} $ →
Yes, it is a factor
#### 3.
$ P(3) = \boxed{0} $ →
Yes, it is a factor
---
📝 Summary Table:
| Problem | Divisor | Remainder $ R $ | Is it a factor? |
|--------|--------|------------------|------------------|
| 1 | $ x+3 $ | 1 | No |
| 2 | $ x-2 $ | 0 | Yes |
| 3 | $ x-3 $ | 0 | Yes |
Let me know if you'd like this filled in on the worksheet format!
Parent Tip: Review the logic above to help your child master the concept of remainder theorem worksheet.