Ella simplifies (3b+4r) + (-2b-r) and says the result is b+5r. What error did Ella make?

A. Ella incorrectly combined the b coefficients. The correctly simplified expression is 5b+5r.

B. Ella incorrectly combined the b coefficients. The correctly simplified expression is - b+5r.

C. Ella incorrectly combined the r coefficients. The correctly simplified expression is b-5r.

D. Ella incorrectly combined the r coefficients. The correctly simplified expression is b+3r.

Question

Mathematics

Andre Sherman

4 July, 18:29

Ella simplifies (3b+4r) + (-2b-r) and says the result is b+5r. What error did Ella make?

A. Ella incorrectly combined the b coefficients. The correctly simplified expression is 5b+5r.

B. Ella incorrectly combined the b coefficients. The correctly simplified expression is - b+5r.

C. Ella incorrectly combined the r coefficients. The correctly simplified expression is b-5r.

D. Ella incorrectly combined the r coefficients. The correctly simplified expression is b+3r.

+4

Answers (2)

Know the Answer?

Starbuck · Answer 1

The correct answer is (D).

(3b + 4r) + (-2b - r) = (3b - 2b) + (4r - r) = b + 3r

not

b + 5r

* Ella added (4r + r) instead subtracting (4r - r), thus she got the wrong answer.

Barkley · Answer 2

D is the answer.

3b + (-2b) = 1b (same as 3-2=1)

4r + (-r) = 3r (same as 4-1=3)

When you add a negative, you subtract.