Chapter 1 - Foundations for Algebra - 1-6 Multiplying and Dividing Real Numbers - Practice and Problem-Solving Exercises - Page 42: 23

-30

We recall that 30 to the second power is 30$\times$30, which equals 900. Thus, we find: $\sqrt {900} = \sqrt {30 \times 30} =\sqrt {30^{2}}=30$ However, there is a negative in front of the square root, so we make our answer -30.