### Home > CCA2 > Chapter 8 > Lesson 8.3.2 > Problem 8-163

8-163.

For homework, Londa was asked to simplify the expression . She got the answer 7, but when she checked, she learned that the correct answer was −7. Homework Help ✎ **Show Londa the steps she could take to get −7.**What steps do you think Londa took to get 7 as a result?

What does she need to consider to avoid making this mistake in the future?

Londa's example means that it is not always true that

*a*and*b*. What restriction needs to be placed on the numbers*a*and*b*?

Look at the negative signs.

Convert to imaginary form before completing operations.

They must be non-negative real numbers.