### Home > A2C > Chapter 7 > Lesson 7.2.4 > Problem 7-142

7-142.

Kirsta was working with the function machine shown below, but when she turned her back, her little brother Caleb dropped in a number. She didn't see what he dropped, but she did see what fell out: 9. What operations must she perform on 9 to undo what her machine did? Use this to find out what Caleb dropped in. Homework Help ✎

In this situation, 9 is the output. Write and solve the equation.

What do you do to both sides of the equation to 'undo' the square root?