What value of b makes the equation below true? Explain or show how you know. (10x-7)(8x + 3) = 80x² + bx - 21

Algebra and Trigonometry (6th Edition)
6th Edition
ISBN:9780134463216
Author:Robert F. Blitzer
Publisher:Robert F. Blitzer
ChapterP: Prerequisites: Fundamental Concepts Of Algebra
Section: Chapter Questions
Problem 1MCCP: In Exercises 1-25, simplify the given expression or perform the indicated operation (and simplify,...
icon
Related questions
Question
100%
**Question:**

What value of \( b \) makes the equation below true? Explain or show how you know.

\[ (10x - 7)(8x + 3) = 80x^2 + bx - 21 \]

**Explanation:**

To find the value of \( b \), first expand the left side of the equation:

\[
(10x - 7)(8x + 3)  
\]

Applying the distributive property (FOIL method):

1. Multiply the first terms: \(10x \times 8x = 80x^2\)
2. Multiply the outer terms: \(10x \times 3 = 30x\)
3. Multiply the inner terms: \(-7 \times 8x = -56x\)
4. Multiply the last terms: \(-7 \times 3 = -21\)

Combine these results:

\[
80x^2 + 30x - 56x - 21 
\]

Combine like terms:

\[
80x^2 - 26x - 21 
\]

Now, compare this with the equation on the right:

\[ 
80x^2 + bx - 21 
\]

By comparing the two expressions, we find:

\[
b = -26
\]

Thus, the value of \( b \) that makes the equation true is \( -26 \).
Transcribed Image Text:**Question:** What value of \( b \) makes the equation below true? Explain or show how you know. \[ (10x - 7)(8x + 3) = 80x^2 + bx - 21 \] **Explanation:** To find the value of \( b \), first expand the left side of the equation: \[ (10x - 7)(8x + 3) \] Applying the distributive property (FOIL method): 1. Multiply the first terms: \(10x \times 8x = 80x^2\) 2. Multiply the outer terms: \(10x \times 3 = 30x\) 3. Multiply the inner terms: \(-7 \times 8x = -56x\) 4. Multiply the last terms: \(-7 \times 3 = -21\) Combine these results: \[ 80x^2 + 30x - 56x - 21 \] Combine like terms: \[ 80x^2 - 26x - 21 \] Now, compare this with the equation on the right: \[ 80x^2 + bx - 21 \] By comparing the two expressions, we find: \[ b = -26 \] Thus, the value of \( b \) that makes the equation true is \( -26 \).
Expert Solution
steps

Step by step

Solved in 2 steps with 2 images

Blurred answer
Recommended textbooks for you
Algebra and Trigonometry (6th Edition)
Algebra and Trigonometry (6th Edition)
Algebra
ISBN:
9780134463216
Author:
Robert F. Blitzer
Publisher:
PEARSON
Contemporary Abstract Algebra
Contemporary Abstract Algebra
Algebra
ISBN:
9781305657960
Author:
Joseph Gallian
Publisher:
Cengage Learning
Linear Algebra: A Modern Introduction
Linear Algebra: A Modern Introduction
Algebra
ISBN:
9781285463247
Author:
David Poole
Publisher:
Cengage Learning
Algebra And Trigonometry (11th Edition)
Algebra And Trigonometry (11th Edition)
Algebra
ISBN:
9780135163078
Author:
Michael Sullivan
Publisher:
PEARSON
Introduction to Linear Algebra, Fifth Edition
Introduction to Linear Algebra, Fifth Edition
Algebra
ISBN:
9780980232776
Author:
Gilbert Strang
Publisher:
Wellesley-Cambridge Press
College Algebra (Collegiate Math)
College Algebra (Collegiate Math)
Algebra
ISBN:
9780077836344
Author:
Julie Miller, Donna Gerken
Publisher:
McGraw-Hill Education