Let’s solve this step by step.
We are given a polynomial to factor:
x⁴ + 8x³ - 20x²
Step 1: Look for the greatest common factor (GCF) in all terms.
All terms have at least
x², so factor that out first:
→ x²(x² + 8x - 20)
Now we need to factor the quadratic inside:
x² + 8x - 20
Step 2: Factor x² + 8x - 20
We need two numbers that:
- Multiply to
-20
- Add to
+8
Let’s list factor pairs of -20:
- 1 and -20 → sum = -19
✘
- -1 and 20 → sum = 19
✘
- 2 and -10 → sum = -8
✘
- -2 and 10 → sum = 8
✔ ← This works!
So, x² + 8x - 20 = (x - 2)(x + 10)
Wait — let’s check:
(x - 2)(x + 10) = x² + 10x - 2x - 20 = x² + 8x - 20 ✔️
But hold on — look back at our factored form:
We had x²(x² + 8x - 20) = x²(x - 2)(x + 10)
But now check the answer choices.
Look at choice
S: x²(x + 10)(x - 2) ← That’s exactly what we got!
Also note: multiplication is commutative, so (x - 2)(x + 10) is same as (x + 10)(x - 2).
So the fully factored form is:
x²(x + 10)(x - 2)
That matches option
S.
Now, according to the instructions:
“Each time the exercise number appears in the code, write this letter above it.”
The problem shown is labeled with a circled
⑤ — meaning this is Exercise #5.
In the “Answers for 1–7” column, find which letter corresponds to the correct factored form for #5.
Looking at the list:
⑤ → ?
We just found that the correct factored form is
x²(x + 10)(x - 2), which is listed under
S.
Check the left column:
Under “Answers for 1–7”, we see:
S → x²(x + 10)(x - 2) ← YES! That’s ours.
So for exercise #5, the letter is
S.
Final Answer: S
Parent Tip: Review the logic above to help your child master the concept of old lawyers never die they just worksheet.