Intermediate Algebra

OPENSTAX

$Math Studyset 91影视 Explanations$ Math

OER 2017 Edition 路 1346 pages

ISBN: 9780998625720

Chapter 6: Q. 156 (page 591)

Tommy factored $x^{2} - x - 20$ as $(x + 5) (x 鈭� 4) .$ Sara factored it as $(x + 4) (x 鈭� 5) .$ Ernesto factored it as $(x 鈭� 5) (x 鈭� 4) .$ Who is correct? Explain why the other two are wrong.

Short Answer

Expert verified

The factors done by Sara's is correct.

Step by step solution

Step 1. Given Information

Tommy, Ernesto and Sara factored quadratic polynomial $x^{2} - x - 20 .$

We need to identify who is correct.

Step 2. Tommy's work

Tommy did as $x^{2} - x - 20 = (x + 5) (x - 4)$

The factors done by Tommy is incorrect because sum of $5 a n d - 4$ is wrong.

It should be $- 1 .$

Step 3. Sara's work

$x^{2} - x - 20 = (x + 4) (x - 5)$

These factors are correct because the sum of $4 a n d - 5$ is $- 1 .$

The product is also correct because $4 脳 - 5 = - 20$

Step 4. Ernesto's work

$x^{2} - x - 20 = (x - 5) (x - 4)$

The factors are incorrect because the sum of $- 5 a n d - 4 i s - 9 .$

It should be $- 1 .$

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91影视

Tommy factored $x^{2} - x - 20$ as $(x + 5) (x 鈭� 4) .$ Sara factored it as $(x + 4) (x 鈭� 5) .$ Ernesto factored it as $(x 鈭� 5) (x 鈭� 4) .$ Who is correct? Explain why the other two are wrong.

Short Answer

Step by step solution

Step 1. Given Information

Step 2. Tommy's work

Step 3. Sara's work

Step 4. Ernesto's work

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91影视

Tommy factored x2-x-20as (x+5)(x鈭�4).Sara factored it as (x+4)(x鈭�5).Ernesto factored it as (x鈭�5)(x鈭�4).Who is correct? Explain why the other two are wrong.

Short Answer

Step by step solution

Step 1. Given Information

Step 2. Tommy's work

Step 3. Sara's work

Step 4. Ernesto's work

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Math Textbooks

Logic and Functions

Probability and Statistics

Discrete Mathematics

Pure Maths

Calculus

Theoretical and Mathematical Physics

Study anywhere. Anytime. Across all devices.

Tommy factored $x^{2} - x - 20$ as $(x + 5) (x 鈭� 4) .$ Sara factored it as $(x + 4) (x 鈭� 5) .$ Ernesto factored it as $(x 鈭� 5) (x 鈭� 4) .$ Who is correct? Explain why the other two are wrong.