Question

Question 4 (Essay Worth 7 points)

[5.05] MA.6.A.3.3

Yuri solved the equation below incorrectly. Explain the step where he went wrong.

fifteen times b plus one equals thirty

Step 1: fifteen times b divided by fifteen plus one equals thirty divided by fifteen
Step 2: b plus one equals two
Step 3: b plus one minus one equals two minus one
Step 4: b equals one

Answer 1

Translate the sentence into a mathematical equation.

Fifteen times b plus one equals thirty.

15 x b + 1 = 30
15b + 1 = 30

Answer 2

The steps to solve this equation for b involve performing "opposite" operations.

The first step would be to subtract 1 from both sides of the equation.

15b + 1 - 1 = 30 - 1
15b = 29

The second step would be to divide both sides by 15.

15b = 29
--- ---
15 15

b = 29/15

Answer 3

Look through the steps that are in the problem. Do you see any that seem incorrect?

Answer 4

Step 1 says that you are dividing "15b" by 15 and "30" by 15.

This leaves out the +1 in the original equation.

Therefore, Step 1 is incorrect because it does not divide each part of the equation by 15.