College

Clara simplifies [tex]\((8b - 4r) - (2b - r)\)[/tex] and says the result is [tex]\(6b - 5r\)[/tex]. What error did Clara make?

A. Clara incorrectly combined the [tex]\(b\)[/tex] coefficients. The correctly simplified expression is [tex]\(10b - 5r\)[/tex].

B. Clara incorrectly combined the [tex]\(r\)[/tex] coefficients. The correctly simplified expression is [tex]\(6b - 3r\)[/tex].

C. Clara incorrectly combined the [tex]\(r\)[/tex] coefficients. The correctly simplified expression is [tex]\(6b + 5r\)[/tex].

D. Clara incorrectly combined the [tex]\(b\)[/tex] coefficients. The correctly simplified expression is [tex]\(-10b - 5r\)[/tex].

Answer :

Let's simplify the expression step-by-step to identify where Clara made an error.

We start with the expression: [tex]\((8b - 4r) - (2b - r)\)[/tex].

1. Distribute the negative sign:

- The negative sign in front of the second parenthesis changes the sign of each term inside it.
- So, [tex]\((2b - r)\)[/tex] becomes [tex]\(-2b + r\)[/tex].

2. Rewrite the expression:

- After distributing the negative sign, the expression becomes:
[tex]\[
8b - 4r - 2b + r
\][/tex]

3. Combine like terms:

- For [tex]\(b\)[/tex] terms: [tex]\(8b - 2b\)[/tex] gives [tex]\(6b\)[/tex].
- For [tex]\(r\)[/tex] terms: [tex]\(-4r + r\)[/tex] gives [tex]\(-3r\)[/tex].

4. Write the simplified expression:

- The correctly simplified expression is [tex]\(6b - 3r\)[/tex].

Clara incorrectly combined the [tex]\(r\)[/tex] coefficients. The correct simplified expression should be [tex]\(6b - 3r\)[/tex], not [tex]\(6b - 5r\)[/tex]. Hence, the error was in combining the [tex]\(r\)[/tex] coefficients.