Question

A retired math teacher tells his niece that they can spend x dollars, and x + 18 = 77.4. What operation does the niece need to use to find out how much money they can spend?

Answer 1

The niece must use subtraction to solve the equation x + 18 = 77.4, which gives x = 59.4. Therefore, they can spend $59.4.

Step-by-step explanation:

The niece needs to perform the operation of subtraction to find out how much money they can spend. To solve the equation x + 18 = 77.4, she needs to subtract 18 from both sides of the equation. This will isolate the variable x on one side of the equation and give the value that x must be in order for the equation to be true.

Here are the steps:

1. Write down the initial equation: x + 18 = 77.4.
2. Subtract 18 from both sides of the equation: x + 18 - 18 = 77.4 - 18.
3. Simplify both sides: x = 59.4.

Therefore, the niece can spend $59.4.