1. **State the problem:** Find factors of 8 and 20 such that when multiplied and then added, the sum is 14.
2. **Identify factors:**
- Factors of 8: 1, 2, 4, 8
- Factors of 20: 1, 2, 4, 5, 10, 20
3. **Set up the equation:** Let the factors be $a$ (from 8) and $b$ (from 20). We want $a \times b + a + b = 14$.
4. **Rewrite the equation:**
$$a \times b + a + b = 14$$
Add 1 to both sides:
$$a \times b + a + b + 1 = 15$$
Factor the left side as:
$$(a + 1)(b + 1) = 15$$
5. **Find pairs $(a+1, b+1)$ that multiply to 15:**
Possible factor pairs of 15 are (1,15), (3,5), (5,3), (15,1).
6. **Check which pairs correspond to valid $a$ and $b$:**
- If $a+1=3$ and $b+1=5$, then $a=2$ and $b=4$.
- Check if $a=2$ is a factor of 8 (yes) and $b=4$ is a factor of 20 (yes).
7. **Verify the sum:**
$$2 \times 4 + 2 + 4 = 8 + 6 = 14$$
**Answer:** The factors are $2$ (from 8) and $4$ (from 20).
Factor Sum 77679A
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