Absolutely! Let’s fill in the blanks and solve each quadratic equation step by step.
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##
✔ First, fill in the definitions:
parabola – the
U-shaped graph of a quadratic function
*(Note: Sometimes called “cup-shaped” or “bell-shaped,” but “U-shaped” is standard for upward-opening parabolas. Downward ones are still U-shaped, just inverted.)*
roots – where the parabola crosses the
x-axis
*(Also called zeros, x-intercepts, solutions — all correct!)*
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## 🔍 Now, let’s solve each quadratic to find its roots (zeros):
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🟢 TWO REAL ROOTS
Equation:
x² + 2x − 3 = 0
We can factor this!
Look for two numbers that multiply to
-3 and add to
+2:
→
+3 and -1
So:
(x + 3)(x − 1) = 0
Set each factor equal to zero:
- x + 3 = 0 →
x = -3
- x − 1 = 0 →
x = 1
✔ Answer: Two real roots: x = -3 and x = 1
*(This matches the graph — it crosses the x-axis at two points.)*
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🟡 ONE REAL ROOT
Equation:
x² + 6x + 9 = 0
This is a
perfect square trinomial!
Notice:
x² + 6x + 9 = (x + 3)²
So:
(x + 3)² = 0
Take square root of both sides:
x + 3 = 0 →
x = -3
✔ Answer: One real root: x = -3 *(a repeated root)*
*(This matches the graph — it touches the x-axis at one point, the vertex.)*
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🔴 NO REAL ROOTS
Equation:
(x − 1)² + 3 = 0
Solve step-by-step:
Subtract 3 from both sides:
(x − 1)² = -3
Take square root of both sides:
x − 1 = ±√(-3)
But √(-3) is
not a real number — it’s imaginary (√(-3) = i√3)
✔ Answer: No real roots — only complex/imaginary roots.
*(This matches the graph — the parabola never touches or crosses the x-axis.)*
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## 📝 Final Answers to Fill In:
Definitions:
-
parabola – the
U-shaped graph of a quadratic function
-
roots – where the parabola crosses the
x-axis
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TWO REAL ROOTS:
> Solve for the zeros:
>
x² + 2x − 3 = 0
> →
x = -3 and x = 1
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ONE REAL ROOT:
> Solve for the zeros:
>
x² + 6x + 9 = 0
> →
x = -3
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NO REAL ROOTS:
> Solve for the zeros:
>
(x − 1)² + 3 = 0
> →
No real solutions (or “no real roots”)
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## 💡 Bonus Tip:
You can also use the
discriminant (b² − 4ac) to predict the number of real roots without solving:
- If discriminant > 0 → Two real roots
- If discriminant = 0 → One real root
- If discriminant < 0 → No real roots
Let’s check:
1. x² + 2x − 3 → a=1, b=2, c=-3 → D = 4 + 12 =
16 > 0 → Two real roots
✔
2. x² + 6x + 9 → a=1, b=6, c=9 → D = 36 − 36 =
0 → One real root
✔
3. (x−1)² + 3 = x² − 2x + 1 + 3 = x² − 2x + 4 → a=1, b=-2, c=4 → D = 4 − 16 =
-12 < 0 → No real roots
✔
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✔ All done! You now understand how to classify and solve quadratic equations based on their roots. Great job!
Parent Tip: Review the logic above to help your child master the concept of solving quadratic equations by graphing worksheet.