Helen wrote and solved the equation.

Question

x minus 17 = 56. x minus 17 + 17 = 56 minus 17. x = 39.

What was Helen’s error?
Helen only needed to add 17 to the left side of the equation.
Helen should have added 17 to both sides of the equation.
Helen’s work is correct.
Helen made a subtraction error when subtracting 17 from 56.

Answer 1

Helen's error was in her method when she tried to solve the equation. The correct approach is to add 17 to both sides of the equation to isolate \( x \).

Let's analyze her steps:

1. She started with the equation: \[ x - 17 = 56 \]

2. Then, Helen performed the operation: \[ x - 17 + 17 = 56 - 17 \]

3. This simplifies correctly to: \[ x = 39 \]

However, in her explanation, it seems she did not clearly add 17 to both sides explicitly, even though her solution arrives at \( x = 39 \) correctly.

Thus, the best answer is: Helen should have added 17 to both sides of the equation.