Math worksheet focusing on using the discriminant to determine the number of solutions for quadratic equations.
Worksheet titled "9.7 Using the Discriminant" with math problems involving quadratic equations and the discriminant formula.
JPG
270×350
21.4 KB
Free · Personal Use
Quality Assured by Worksheets Library Team
Reviewed for educational accuracy and age-appropriateness
ID: #427833
⭐
Show Answer Key & Explanations
Step-by-step solution for: Algebra Essentials 9.9 Using the Discriminant Worksheet (DOCX & PDF)
▼
Show Answer Key & Explanations
Step-by-step solution for: Algebra Essentials 9.9 Using the Discriminant Worksheet (DOCX & PDF)
Problem Overview:
The task involves using the discriminant of a quadratic equation to determine the number of solutions. The general form of a quadratic equation is:
$$
ax^2 + bx + c = 0
$$
The discriminant, denoted by \( \Delta \), is given by:
$$
\Delta = b^2 - 4ac
$$
The number of solutions depends on the value of the discriminant:
- If \( \Delta > 0 \): The equation has 2 real solutions.
- If \( \Delta = 0 \): The equation has 1 real solution (a repeated root).
- If \( \Delta < 0 \): The equation has no real solutions (complex solutions).
Step-by-Step Solution:
We will solve each quadratic equation step by step, following the instructions provided in the image.
---
#### 1. \( 2x^2 + 5x + 3 = 0 \)
1. Identify coefficients:
- \( a = 2 \)
- \( b = 5 \)
- \( c = 3 \)
2. Write the discriminant formula:
$$
\Delta = b^2 - 4ac
$$
3. Substitute values into the formula:
$$
\Delta = (5)^2 - 4(2)(3)
$$
4. Simplify using the order of operations (PEMDAS):
$$
\Delta = 25 - 4(6) = 25 - 24 = 1
$$
5. Determine the number of solutions:
- Since \( \Delta = 1 > 0 \), there are 2 real solutions.
Answer:
$$
\boxed{2}
$$
---
#### 2. \( x^2 + 6x + 9 = 0 \)
1. Identify coefficients:
- \( a = 1 \)
- \( b = 6 \)
- \( c = 9 \)
2. Write the discriminant formula:
$$
\Delta = b^2 - 4ac
$$
3. Substitute values into the formula:
$$
\Delta = (6)^2 - 4(1)(9)
$$
4. Simplify using the order of operations (PEMDAS):
$$
\Delta = 36 - 4(9) = 36 - 36 = 0
$$
5. Determine the number of solutions:
- Since \( \Delta = 0 \), there is 1 real solution (a repeated root).
Answer:
$$
\boxed{1}
$$
---
#### 3. \( 4x^2 + 3x + 2 = 0 \)
1. Identify coefficients:
- \( a = 4 \)
- \( b = 3 \)
- \( c = 2 \)
2. Write the discriminant formula:
$$
\Delta = b^2 - 4ac
$$
3. Substitute values into the formula:
$$
\Delta = (3)^2 - 4(4)(2)
$$
4. Simplify using the order of operations (PEMDAS):
$$
\Delta = 9 - 4(8) = 9 - 32 = -23
$$
5. Determine the number of solutions:
- Since \( \Delta = -23 < 0 \), there are no real solutions.
Answer:
$$
\boxed{0}
$$
---
#### 4. \( 3x^2 + 6x + 3 = 0 \)
1. Identify coefficients:
- \( a = 3 \)
- \( b = 6 \)
- \( c = 3 \)
2. Write the discriminant formula:
$$
\Delta = b^2 - 4ac
$$
3. Substitute values into the formula:
$$
\Delta = (6)^2 - 4(3)(3)
$$
4. Simplify using the order of operations (PEMDAS):
$$
\Delta = 36 - 4(9) = 36 - 36 = 0
$$
5. Determine the number of solutions:
- Since \( \Delta = 0 \), there is 1 real solution (a repeated root).
Answer:
$$
\boxed{1}
$$
---
#### 5. \( 2x^2 - 4x + 2 = 0 \)
1. Identify coefficients:
- \( a = 2 \)
- \( b = -4 \)
- \( c = 2 \)
2. Write the discriminant formula:
$$
\Delta = b^2 - 4ac
$$
3. Substitute values into the formula:
$$
\Delta = (-4)^2 - 4(2)(2)
$$
4. Simplify using the order of operations (PEMDAS):
$$
\Delta = 16 - 4(4) = 16 - 16 = 0
$$
5. Determine the number of solutions:
- Since \( \Delta = 0 \), there is 1 real solution (a repeated root).
Answer:
$$
\boxed{1}
$$
---
#### 6. \( 3x^2 - 7x + 5 = 0 \)
1. Identify coefficients:
- \( a = 3 \)
- \( b = -7 \)
- \( c = 5 \)
2. Write the discriminant formula:
$$
\Delta = b^2 - 4ac
$$
3. Substitute values into the formula:
$$
\Delta = (-7)^2 - 4(3)(5)
$$
4. Simplify using the order of operations (PEMDAS):
$$
\Delta = 49 - 4(15) = 49 - 60 = -11
$$
5. Determine the number of solutions:
- Since \( \Delta = -11 < 0 \), there are no real solutions.
Answer:
$$
\boxed{0}
$$
---
#### 7. \( 2x^2 + 4x + 3 = 0 \)
1. Identify coefficients:
- \( a = 2 \)
- \( b = 4 \)
- \( c = 3 \)
2. Write the discriminant formula:
$$
\Delta = b^2 - 4ac
$$
3. Substitute values into the formula:
$$
\Delta = (4)^2 - 4(2)(3)
$$
4. Simplify using the order of operations (PEMDAS):
$$
\Delta = 16 - 4(6) = 16 - 24 = -8
$$
5. Determine the number of solutions:
- Since \( \Delta = -8 < 0 \), there are no real solutions.
Answer:
$$
\boxed{0}
$$
---
#### 8. \( 2x^2 - 4x + 3 = 0 \)
1. Identify coefficients:
- \( a = 2 \)
- \( b = -4 \)
- \( c = 3 \)
2. Write the discriminant formula:
$$
\Delta = b^2 - 4ac
$$
3. Substitute values into the formula:
$$
\Delta = (-4)^2 - 4(2)(3)
$$
4. Simplify using the order of operations (PEMDAS):
$$
\Delta = 16 - 4(6) = 16 - 24 = -8
$$
5. Determine the number of solutions:
- Since \( \Delta = -8 < 0 \), there are no real solutions.
Answer:
$$
\boxed{0}
$$
---
Final Answers:
1. \( 2x^2 + 5x + 3 = 0 \): \( \boxed{2} \)
2. \( x^2 + 6x + 9 = 0 \): \( \boxed{1} \)
3. \( 4x^2 + 3x + 2 = 0 \): \( \boxed{0} \)
4. \( 3x^2 + 6x + 3 = 0 \): \( \boxed{1} \)
5. \( 2x^2 - 4x + 2 = 0 \): \( \boxed{1} \)
6. \( 3x^2 - 7x + 5 = 0 \): \( \boxed{0} \)
7. \( 2x^2 + 4x + 3 = 0 \): \( \boxed{0} \)
8. \( 2x^2 - 4x + 3 = 0 \): \( \boxed{0} \)
Parent Tip: Review the logic above to help your child master the concept of discriminant worksheet.